What are you currently shooting? I love my Phantoms but they can be an acquired taste. If you want super light weight and probably go stockclass look at a used Phantom if you are going to run open class go with the trilogy.
like said before the phantom and the trilogy are two TOTALLY different guns phantoms are not always fancied by most speedball players just because they have no regulator to hold onto. if you are converting from shooting a semi a trilogy would be the better option because they are usually cheaper than a phantom and have the reg to hold onto. Overall it comes down to personal feel and taste for the marker and welcome to the world of pump!
You want an opinion? Here's mine: I like my Trilogy better than every Phantom I've tried. It has a smoother pump stroke, seems to be more consistent (can't really get any better than my Trilogy's +/- 2 fps...on a BAD day), and it just feels better all around. Plus, it obviously takes Cocker barrels. My buddy is getting barrel breaks all the time with his Phantom's detent rings.
Phantoms are lighter though -- almost TOO light for my taste. If you want to go stock class though, Phantoms are definitely money.