The only ones you really need to worry about are Scis; Escorts will be packing damage buffs regardless, and Cruisers will be packing high level heals, with DEM 3/Extend 3/A2SIF 3/EWP 3. 3 out of the 4 you don't really need to be aware of (nothing you can do about DEM and A2SIF, Extend is obvious and can be worked around) and the 4 isn't too terribly hard to avoid (EWP).
Scis, though, are a whole 'nother story. But, within the first minute of the match, you usually know what you're up against.
I usually /tell Player@Noobsauce "hey what you got on that thing" Most of the time detailed information follows. Especially if theyre running good stuff they LOVE LOVE LOVE to brag about it!
heck, I'll tell everything... except the one or two things I see as my own specialty! And I think this is true for most captains. Unfortunately, these little things are usually the difference between awsome and useless... :p
When you target a ship, you get the choice of scan, if you scan it a 3d holo image of the ship pops up, freely positionable on the screen, that shows you the shape and slotted equipment. power levels as a general guideline, higher then yours, lower, same level kind of deal. Just a rough idea what they are no precise numbers. the longer the scan is running the more details you are getting. for example after 5 seconds, a lifesign status, 64% human, 12% andorian, 1% borg etc. more details about the equipment, like it starts with phaser beams, after a few seconds, it reads mark 10 phaser beams, etc.