Had the pleasure of picking up a Tippmann Phenom last Saturday, as an upgrade to my A5, and I used it all day.
Basically I was very impressed.
Because the Phenom is working below 300 psi and theres no hammer at the back end of the gun you seriously notice there's no vibration when you shoot. This helps every shot stay on course, rather than an A5 which shakes the hell out of a gun, causing the paintballs to get very excited....and spray in a wide pattern. I didn't measure the shot spread but I know it was a lot tighter than the A5. More consistent and more accurate.
I played all day with a .688 JJ and Apex tip and didnt have a single break from a mix of Diablo Heat and XO Spectrum, which was pretty damn amazing. Air usage also appeared to be half of what I would normally run through on a game using the A5.
I did think an S2 or two piece JJ would not allow the shroud to fit, but the shroud contains a circular front piece that can be removed to widen the barrel hole...and all the A5 JJ's fit perfectly.
The A5 stock however does not fit, as Tippmann have moved the lower pin by about 1/8", but obviously that happened at the time of the standard X7, not the Phenom.
Inside there's hardly anything to it. No springs, no o-rings, no tombstones, no hammers etc....the Flex Valve is all sealed. Take the back cap off and nothing falls out of the gun.
The trigger should be black as opposed to silver and the battery compartment could be tighter, but all in all what a cool gun.
D.