I haven't tried an Infinette, but I am a very proud owner of an Infinity
I have to say I think these two instruments are very similar, both in sound and physics. Yes, the PU's are placed a little different, but I still think they sound very similar.
When you play the Infinity you'll feel that the balance of weight is perfect. I can also honestly say that the Infinity is the most comfertable bass guitar I've ever tried. The sound is amazing, and you got
loads of tone possibilities! From vintage sound to high end botique sound. The hollow body does wonders. Try boosting the mids if you try one, it really sounds like a hollow body. It's also a slap beast.

EDIT: Forgot to mention, the growl is insane!
The Infinette looks to me similar to a Corvette when it comes to balance, just much lighter when we speak weight. I cannot speak for the sound, as I've never tried one.
One thing is for sure, if I was you I wouldn't hesitate buying an Infinity if you got the money for it, it's sure expensive. And it would also be much easier to find an Infinity than an Infinette
cheers, blikeng
PS. Sorry if I went over the top describing the Infinity

It's just so goddamn awesome.