From reading threads, I was planning on a 3.5 ecoboost because of the greater power and you can chip it for even more HP. But 3 things are making me sway towards the 5.0.

1) The internet has been fairly quiet about the fact that the 5.0 got bumped up to 385HP for 2015.

2) I like V8's better (sound, simplicity, etc)

3) My brother in law just traded a 2010 5.4 F150 for a 2013 ecoboost and he's unhappy with it. He says sure there is more power once the turbos spool up, but in heavy traffic (where I live), when you want to keep up with the car in front of you, it's easier with the v8 instant torque. With the eco, it's a little slow building up, then takes off like a rocket.

I haven't driven either, and sitting here at work in my cubicle, though I'd start a discussion about the driving characteristics of each engine.

 

I haven't driven both in the 2015's, but I did some bac-to-back drives in the last generation truck, so it's probably still relevant.

- Sound, if you want the v8 sound, you should get the v8. Some people like the sound of the EcoBoost, but not many.
- Turbo Lag, Yep, the EcoBoost has it, and if you are constantly on and off the throttle, I can see that some people would find that annoying. Personally, I just adjusted my driving style over time, and I don't find it annoying driving daily in city traffic.

In all honesty, the 5.0 V8 is a fabulous engine. If they've bumped the power in he new lighter 2015's, then it's going to shine that much more.

I still like the EcoBoost more.

 

It is not difficult for the Ecoboost to keep up with traffic. It is a bit difficult to closely pace (tailgate) normal cars because of difference in power band, not because of turbo lag. The Ecoboost is ready to move out at lower rpm than other cars so the tendency is to run them down and have to let off the throttle. Right about that moment the other cars get in their power band and start to move away. It's that constant rubberband effect of unsynchronized power curves. Again, this is only a problem if you are driving aggressively and the guy in front of you slows you down. If you just chill out a bit and give yourself a little more following distance then you can drive at a smooth pace.

 

I have, and the EB feels snappier to me. The sound inside the truck is almost as quiet as my living room (an exaggeration, but not by much), so the engine sound is extremely muted to me.

But if you have an emotional attachment to a V8, go with the 5L; it's a great engine.

I ended up with the 3.5EB, and it is one of the smoothest things I have ever driven.

 

I've driven them back to back, but it was a more aggressive driving course which is different than low idle RPM. Any sort of spirited driving quickly goes to the Eco-Boost. A V8 is probably better for "grandpa" driving, be it by choice or traffic.

Ford list the torque of Eco-boost 420@ 2500 rpm and the 5.0 with 387 @ 3850 rpm (Source Ford.com)

I don't think it's about low RPM torque, but rather the smoothness the torque is delivered. I think many people don't realize how much power they are making with gentle acceleration on the ecoboost. A good salesperson will let you drive them back to back, just be courteous and let the salesperson who spends the most quality time with you get last crack at giving you the deal.

 

I have driven both. What really turned me off to the 3.5L ECO boost was when out on the demo ride with the Ford rep. (not a dealer rep.) driving the 3.5L and I said it sounds good like a V-8 and he said "that is because it plays the V-8 sound through the radio on the Eco-Boosts. Ummm no thanks. I will have the real V-8.

 

I hate fake sounds too. It's been a growing trend over the years with most manufactures. I suppose if you were tricked by it then it does a good job.

 

Yes, this is the best description yet. It is aggravating for sure till the knot head in front of you is nice enough to get over or on with it.

 

That's contradictory. Grandpa will drive at lower RPM, where the EB makes it's torque, and the 2015 5.0 is more suited to the Muscle car lover due to the Higher horsepower (385HP Vs 365HP) and RPM. I've yet to have a Ecoboost pull away from my stock 13 RCSB 5.0 (even at 360HP). That is one fun package.

 

I could but mine's not stock so that's not a fair comparison.

 

That may be it. The first EB I ever drove was a 2.7EB Lariat, and what impressed me the most was that I was steadily pushing the throttle down a "little more" and that darn thing just kept pouring it on. Very impressive; especially considering the displacement.

I then drove a 5L, XLT IIRC, and it was stronger, but more sedate. I think that was my gut impression, strong, but sedate.

Finally I drove a 3.7EB, and whooee. That baby would boogy!

We just picked our 3.7EB XLT yesterday, and it is really impressive. Needed to get on it merging into freeway traffic, and it was in the groove in no time. Something else I didn't see when I test drove, but was able to see when I drove it home was there are points where when you step on it a "little", and the response you get is a "lot". So it depends somewhat on where you are in terms of RPM/speed/gear and the response seems very aggressive.

 

Yes, I think you'll like your 3.5 Ecoboost.

 

I've driven both back to back several times and did it about two weeks ago. The 3.5 EB has much better acceleration and low end torque. I'm not sure about the lag as it was not really noticeable on the ones I've driven.
The 5.0 is close but it doesn't have the low end torque the EB has.

If you tow the 5.0 will get better mileage. If you live in hilly terrain the 5.0 will get better mileage for sure.
The EB will be more fun to drive as it seems like a rocket ship going from 55-90 faster than you'd like.
The 5.0 can't do that as smoothly as the EB engine.

Younger people will like the power of the EB over the 5.0. It's just more fun to drive. The problem is if it's in boost too much the mileage will really suffer.

I can't stand the piped in fake sound of the EB. I actually like the quiet sound of the engine much better. Why Ford thinks they need to make the truck sound like a V8 is beyond me.
I've not seen an EB that will get the mileage most want out of this engine. We see just under or at right close to 17mpg most of the time traveling 75+ in all of my friends trucks with the 3.55-1 gears. Towing they get right around 8mpg with a 6K trailer.

I think in the long run the 5.0 will be a more reliable long term option but that has yet to be proven.

There's really not much of a difference in price for a step up to the EB so cost shouldn't be an issue on a 40K truck..
I drove the smaller EB and there's no way I would buy it over it's bigger brother or the 5.0

I've driven both engines enough and I'm currently in the market for a 5.0 F150. The 5.0 just fits what I need better.

 

Maybe it's a 3.5 EB with a 3.73-1 gear

 

I drove them both back to back and went with the 5.0. This is just a slight spin on a very old debate. Everyone needs to look at what they want out of their truck and get what fits their wants. I still think the ecoboost engine is going to be less reliable because of the turbos and any gas savings are eaten up in extra purchase costs. Besides that, most ecoboosts drivers are running premium fuel and they should because the performance is better with premium on that engine.