Yeah, what HELMUT said.
Really, it's probably not that much fun to field e.g. any lone PACK ship at all, unless you are very patient and / or a masochist.
The highly combat-capable [CB] type ships are very strong, but typically you won't be carrying enough logistics support to have fun with them on their own - so make sure they have logistic support.
If you wanted an early stage fleet that can punch above it's weight, picking from the basic skins - the Wirefox is an excellent 'kiter' against most fleets, but you'll probably need a couple of Samoyed (Base) to bring in more firepower / distractions to be able to reliably take on any kind of fleet above one or two ships (and even then, it's very sensitive to mistakes). The Caomarelo Samoyed (Base) are ridiculously quick, and eminently survivable - in the AI hands - and are a reasonably cheap effective combat option (but will have a constant supply drain due to being overclocked).
If you want to move up a level, try a Pitbull, but you WILL want a couple of escorting Schnauzers (or Bedlingtons?) to back you up, as the Pitbull is very slow but can slaughter things once it gets the Ripsaw in range (assuming you don't get flanked ...). The Pitbull is a bit more forgiving (it has decent armor), and has huge potential forward firepower just due to the four front facing missile hardpoints - Jets make it maneuverable in a pinch, but positioning overall is important as without the Jets they are pretty lethargic. The Pitbull [CB] may make you feel invulnerable due to hardened 360 shields ... I've found that not to be the case - but it can do (and take) a lot of damage over the course of a battle.
For more 'fun' - try piloting the Shar-Pei. This one definitely needs protection from flanking AND probably escort PD, and I guess was balanced against the inferior Missile AI of a few versions ago - so probably sucks more than it should - but can be rewarding to play and requires skill to use effectively (probably not really that suitable for AI, unless you want to send a bunch of crew to an early space-grave).
You're supposed to mix craft up, really, due to the relative strengths of the ships. I've found lot's of mixes of craft work - but sticking to one type can often be a recipe for disaster (I find that without a sufficient mix of craft types - you can go from hero to zero very quickly, particularly when you come against a problem fleet, and larger craft need particular care whilst fielding a PACK fleet - try Pitbulls or [CA] Schnauzers to bring the Reapers).