What I've owned for the last two years (not counting speedball stuff)
X-7 / polished internals / Opsgear G36 barrel / Vortex ratchet / Squishy Paddles / modded bolt 
I quickly learnt to dislike that gun. Shot decently only after some extensive modding, including what I called the 'J-Bolt': I basically glued an O-ring to the bolt tip using gel Loctite, thus eliminating chops. But I only used it as a loaner for kids with crappier guns still, or for those limited-ammo tac cap games only.
SP-8 / EOS-Epiphany internals / Blackheart board / CP reg / Firebolt / Tactical Freak front + Freak back + SS inserts 
I loved that gun. Shot like a dream. Except that the stock SP reg was a dud, so I replaced it with a CP reg. I loved the feeling of carrying a huge 'sci-fi' rifle, made me feel like I was in Halo or Aliens! With the EOS/Epiphany internals I eliminated drop-off and dramatically improved consistency, but the internals barely supported the higher pressures. It was like my "Millennium Falcon": a great performer but required quirky maintenance. The only thing that I really didn't like was the cheap plastic; it would crack or come unglued. Whenever I got back home after a game and cleaned my stuff I often had to put epoxy all over to fix the body... that's an odd feeling for a PB gun. When I sold it (a move that I deeply regret) I went back to Ion internals and it shot great (and all the quirks were gun).
SP-1 / Blackheart Board / L7 bolt / Flasc 9" barrel 
Still use it as my primary, never thought I would. I bought it back when they were $150 back in 2008. I bought it as an afterthought, I wanted to boost my order at Badlands to get better pricing. In 20 odd years of 'ballin' hands down THE best gun I have ever owned. I liked it enough in its stock form, I absolutely love it with the upgrades. I can shoot 15bps on full-auto all day long, no breaks nor chops, no drop-off, consistent, super accurate, I get maybe 1200 shots out of my 45/68 tank... what more do you want??? Some variations include a Freak barrel with Apex tip (for those crazy long-distance shots) and my current one: minus the stock (gets in the way when playing indoors as I do this time of the year) and sight raiser (damn' heavy)
TM-7 / 9" Flasc barrel
Bought that one at a discount. Good gun, but my SP-1 was superior and promptly sold it. The thing that really pissed me off was that it wasn't working properly out of the box... as most TMs tend to do. Luckily I'm not too shabby with teching stuff so I changed the lube to Dow Corning and cleaned the 'noid. It was golden afterwards. But the stock trigger was absolutely horrendous. Still, I'm in the market for another one now that the prices have dropped big time and this time I'll mod it to my liking.
X-7 Phenom / 8" Lapco barrel
I bought that one on Boxing Day for a ridiculously low price. Good effort by Tippmann, it has many cool features. But as with the TM-7, I felt it was sub-par to my SP-1 in a few key categories. I was really impressed by the fact that it is the first Tippmann I see doing good consistency. Maintenance is a joke and the internals seemed very sturdy. Missing from the pic is the X36 folding stock.
M-Tac / 9" Flasc Barrel 
My latest acquisition. The quality on this gun is absolutely amazing. I only played two games with it and it kicks butt. It was very easy to tune with the pressure tester, and once you get around the programming instructions (which you have to hunt down on the net) it is very simple to operate and maintain. So far, so good. I'm sending her in to California in a few weeks to get the 'Supercharger' mod, the newer steel detent and 4C eyes.