First, what kind of money are you looking to spend? Xscream's stuff is the most expensive but, there is a reason for that.
Second, you have to remember with Dasa it all depends on who builds it. A Hiro built Dasa can't even compare to a Blowsion built Dasa. With a XS engine they are all built by the same guy, Chuck, and all built right.
It also depends on what style of riding you do. That's where you test riding everything comes into play. I'll get more into this later.
My opinion:
They all have enough power for you.
I think Dasa and TPE have a huge amount of bottom end, more than a XS. I think between the Dasa and TPE, the TPE is better. It has more bottom end snap and pulls a little better than a Dasa.
I feel both those lack in true "power" when compared to a XS engine.
A XS1200 doesn't have that super snappy bottom end but, pulls like a freight train mid to top, enough to scare you, enough for you to be scared to pull the throttle all the way.
Now, that's where your ride style comes into play. If you just want to go out and do a single trick I'd say a Dasa or TPE is more up your alley.
If you want to do big combos I'd say XS1200 all day or even a XS900rr. During a combo when you land your first trick and go for the second trick you are already past the low end of the powerband. That's why you want more mid to top, to pull you thru the next trick.
Even with all that said, the best thing you can do is test ride all of them before dropping the coin