The 2 valve V10 did not flow air very freely, and had quite a bit less power than the 3 Valve V10's. I had one of each, with another 3 Valve on order. Comparing the 3 Valve:

The SD 6.2 reaches it's max HP of 385 @ 5500 RPM.
The 3V V10 reaches it's max HP of 362 @ 4750 RPM.

23 HP more, but at 750 more RPM. 6.5% more HP @ but 15% more RPM to get it, Pretty much a toss up.

The 6.2 (using the F250 rating) reaches its max TQ of 405 @ 4500 RPM
The 3V V10 Reaches it's max TQ of 457 @ 3250 RPM The 3V V10 has 90% of it's torque available by only 1600 RPM (more than the 6.2 puts out at any RPM)


That's 52 TQ more, at 1250 RPM less, or about 38% less rpm to achieve 13% more TQ.
Clearly a V10 win.

That adds up to the V10 having a way more usable power range. Overall win in power goes to the the 3V V10. The 6.2 will get about 10% better fuel economy.

I'm not saying the 6.2 is weak, only that the 3V V10 is better in power for those actually working them. Unloaded, the 6.2 should be just as quick because of the 6 speed auto trans (The V10 still only comes with a 5 speed auto) The 3V V10 will tow better.