Engines to buy:
O.S., RB, and Novarossi. Plenty of different models to suite anyones needs. I have personally owned only a small number of engines. AE .15 (i didn't like it), Ofna .15 Pro S (didn't like this one either), O.S. .12 CV-R (very nice, consistent carb), RB X .12 5 port turbo (haven't tried it, but finish is superb). I'm planning on getting an MT .12 turbo as well before running my 5 port.
Engine to consider:
The Piccos had some quality issue before, but their new line of high powered .12's look promising. I'm gonna keep an eye on the Ofna/Picco 7 port. I wouldn't waste my money on the older Trinity/Picco var. But if you want a safe engine right now, go to O.S., RB, and Nova; you cant go wrong with those 3.