I would have to say that I use both methods (flourescent tube +heat and powersun ) on two different tanks of course. These are my opinions and experiences with these bulbs.
Overall, I would say that the zoomed Powersun has proven itself worthy. My female (whose cage it is hanging above) has wonderful colors, is VERY active, and basks under all day. If you do use the Powersun mvb, I highly recommend buying a lamp stand of some sort since you cannot use a dimmer switch on them (or have them angled in a socket). This is a great bulb of the commercial type.
PROS: very active, color intensifying, happy beardie. You can really see the difference! (especially in mbd cases, in which I am currently treating and using with a Veiled Chameleon)
CONS: expensive. the bulb must be adjusted in height - if it gets too hot, you've got to raise it up with the lamp stand, if it gets too cool, you have to lower it. WILL blow out in a power outage if not attatched to a surge protector (my boyfriend has gone through 3 bulbs for this reason)
In addition, DO NOT touch the bulb with your hands. The oils on your fingers, especially with any zoomed type bulb, have been known to blow out for these reasons as notified by zoomed representatives.
The zoomed ReptiSUN 10.0 flourescent tube is nice to have in conjunction with a heating lamb because a) I can use a dimmer switch on the heating device without affecting the UVB output of the flourescent and b) it doesn't hand over the cage or get in the way (but thats because I have it mounted with heavy duty velcro strips in the INSIDE of the cage). My male fairs well with it and I haven't had any problems with it, but I do feel the powersun really brings out the colors of your bearded dragons more.
PROS: reasonable in price (comes in handy for those 6 month replacements), slim and not bulky, decent output, can be placed inside the cage where screens do not filter out the UVB output. My basking bulb can be altered with a dimmer switch w/o affecting the
UVB bulb <---- very important feature for someone who lives on the third floor.
CONS: well, other than not having the heating/basking feature, its pretty awesome.