Welcome to the
Dark Side 
I truely think that you are going to be floored by the difference in sound between tubes and solid state. Everything will come to life and be WAY more fun to listen to.
Having said that and not having heard the amp before, give it a solid couple of weeks (100 hours or so) of play time before you make a judgement about how it sounds. Reason I say that is typically the coupling caps (between the tubes) take a bit to run in fully. It might sound a little dodgey (focus, soundstage, maybe a bit of grain, stuff like that) until they get some hours on them.
The great thing about tubes is, if you don't care for the sound, you can change it as easily as changing the tubes. If you still don't care for the sound, a quick, easy and cheap coupling cap change out can dramatically change the sound of the amp (Blackmore and Mike D can attest to that).
You might also ask the guys at AV123 if you can substitute 6L6's, EL34's and KT-88's in the amp. Again, not knowing the amp, this should be a simple bias adjustment (unless the amp is self biasing (a fixed resistor)) to handle teh new tubes. That will open up the amp for lots more sound possibilities.
Noticing that Rockets are 6 ohm speakers, you may want to contact the guys at AV123 and see what the minimum ohm rating for those speakers are (and at what frequency). This will determine which taps you want to use (4 or 8 ohm). Guessing, the 4 ohm tap will probably sound best but that is a pure guess.
Enjoy!
