Morphyx:
I though I would answer your questions, and then suggest two ideas. I have an XP50 plus expansion boards. It works the same way.

1)overall, are you happy with the sounds compared to other synths?
Yes, Yes, Yes,
2)can cubase or other sequencer access patches from the expand boards at the same time as the normal patches? for exmp: midi chan#1bass/#2piano/#3organ/#4techno sound/#5session sounds/6#orchestrl etc?
Yes, Yes, Yes
3)is it the same as a xp60 without the sequencer...are the effects different?
Same sounds.. same effects, no sequencer
4)overall,..is it a good quality product or more like an entry level synth
I think the keyboard is light in action, but of high quality.
5)can you save patch tweaks to the bank/patch# it's at or only to the smartmedia cards?are the factory presets permanant?is there a user bank?
There is a user bank. There are thousands of patches which usese of the JV/XP series have posted on the web.

OK here are my two suggestions.
1)Wait till you are established in the band and happy in your guitar role before looking for a synth.
2) Based on the description of yourself and your music, you might first consider whether you want a rom machine(XP30) or a virtual analog machine like the yamaha AN1x ($499 if you can still find one). If a few tasty analog sound effects and pads (a la Geddy Lee) are going to be more useful to you than 20 different saxophone sounds get a VA. Just a thought. Trouble is, most virtual analogs are deficient in the emulation of natural instruments like piano and organ. If you decide on a rom based machine, you can do no better than an xp30 IMO.