I've had a 154/3 since it came out and after one ride I moved the limiter strap up one hole, to make it even more wheelie-ish (aka responsive to throttle and weight position). It's a party sled, even in just a few inches of fresh. Not the best for straight up pokes on the steepest faces, but you can make it work, once you figure out how to ride it. Definitely more athletic. And I disagree about the 2.5" tracks. My backup sled is an XM w/ a 2.5 and while it's fun to spin the track, and sometimes even an advantage, but not better on balance. I care the most about track performance when it's deepest. When I'm breaking trail in the woods and just barely making it, the paddle makes a huge difference. Would never go back. My best riding buddy has an '18/165 and it's plenty fun, but not the same. It's easier to hold a sidehill on it, but that's not my highest priority I'm 5'10"/170# though, so maybe the 165 would feel like a 154 to you.
I think a lot of it depends on the snow. THe bottomless, dry fluff, the 3" is king. On wetter, more setup snow, the 2.5 works pretty darn well. I've had a 14 XM 154 x 2.5, 17 G4 154 x 2.5, and now a 18 G4 154 x 3.0. The different pitch on the G4 makes the 2.5 on the 154 noticeably more capable than the 2.5 on the XM. It gets up out of the snow a fair bit quicker and just seems to hookup and perform better. The 3.0 changes the personality of the machine. The 2.5 feels more playful - the rear end can be broken loose when you want to adjust a line, it builds RPM quicker, it's just generally more of a dirt bike feeling than the 3.0.
The 3.0 is a tractor. It accelerates noticeably slower and when you have a line held, it's not overly difficult, but it's tougher to break and readjust. The 3.0 contributes a lot to the ski lift. As with any other length, you can go slower through the trees with the 3.0 and when you need it to dig in and pull you out it will just keep chewing until it finds something to hook on. In those cases, the 2.5 will just dig itself a hole.
Keep in mind, most of the snow I ride in is relatively wetter, more setup snow. I have both a 2.5 and a 3.0 for my 154. Both tracks have pros and cons, but I think I ended up riding the machine with the 2.5" track on it more than the 3.0. In my experience, the 3.0 is equally as capable as a XM with a 163 x 2.5.