Forgot to add earlier that I got to try out quantum torps for the first time. I'm kinda torn on them though. They are definitely sweet when trying to stuff a salvo up someones tailpipe given their above average speed, but they are somewhat detracting in that the reload time is just as noticeably longer than photons. I would almost think that having both on a larger vessel would be nice as you could open with quantum, spam photon as range closes, saving a snapshot quantum load when you have a shields down moment.
I finally made a wholesale switch to quantums after getting a green the other night. At first my observations were that the damage difference between quantums and photons was negligible (amounted to about 50 damage, NOT dps) while photons have a distinct advantage in dps. I made the switch to quantums and started dumping points into the torpedo skill, which arguably will improve photon torps as well, but that's where the point damage difference kicks in.
Quantums are used best with High Yield Torpedoes, utilizing your energy weapons to knock out a shield then deliver the kill shot with the torpedoes. It becomes more about burst damage rather than sustained damage - something which flying an escort that does some 1300+ dps with energy weapons (without buffs) is easy to do.
One thing to remember about torpedoes in general - they ALL share a cooldown timer. It looks like they've changed it slightly, making it better overall, but there is a minimum 3 second global cooldown on all torpedo tubes across your ship - meaning you
can not fire more than one torpedo at once. Photons get a 6 second cooldown, quantums 8, and the next grades 10. Worst case scenario in terms of timing, you're looking at 11 seconds between quantums or 9 seconds between photons if you're alternating. There is a best case as well, which is roughly 5 seconds between shots. Because of the non-linear cooldowns, this value will slide around. Your best bet will be keeping multiple of the same type of torpedo launcher rather than mixing in order to maximize fire times.