I got the JHAS for 165M EC on the exchange a while ago. They will be down to that again soon I think. It's a great escort, for sure, and the main thing my KDF Tac uses. I'm not wild about it, perhaps as I don't yet PVP, but I do like it.
I have the Armitage as one of my main Fed Tac ships and really like that. I have tried Elite Scorpions and Danubes and might also have a look at a tanky shield drone build. 2000 Zen for this.
I am seriously considering a fleet Defiant now as we approach T3. 2500 Zen (2000 for standard ship plus a 500 upgrade to fleet, the only way to do it and have a cloaking console).
Thing is, there are also so some nice free options:
The Mirror escorts are as low as 40,000EC on the exchange which is nearly free. Good, solid escorts that will be fun. I always liked my T4 AE Escort.
The 'ice race' Breen is great and it has the slots etc. to make a wicked plasma build ESTF ship. I really enjoy this. Pointless suggestion if you don't already have it, I guess.