I can answer about G-70.

Quote:
Originally posted by hellboy44:
1. Does the G-70 have enough sounds and styles at it's disposal to sound more "cutting edge" then past Rolands - they sound great for live acoustic instruments, (especially drums) but what about electronic loops/beats/kits??

I've always had to work hard to get the VA to sound (VERY) up to date (ironic, since Roland came up with most of the Drum machines used in today's (and yesterday's) Dance music...)

In spite of what is often said, G-70 has several new fresh sounds compared to VA-7.
Unfortunately for you no change is present in electronic drums department, where you will still find the same sounds of your VA-7, but you can take advantage of the single drum sound equalizer to customize and adjust the sounds according to your taste and needings.
Big improvements in acoustic drums is present in E-80, but I see that you are looking for a 76 keys; in this case you can consider the E-60 that has a sound set similar to E-80 and has 76 keys, even if the keybed quality in not same as (wonderful) G-70 action.

Quote:
Originally posted by hellboy44:
2. Are the SRX boards any good? I would like to use the extra sounds - namely the rhythm loops - in the styles, or however I want to really - apparently OS 3 will let you do this , I hope it's a painless process!!! (Are they worth all that money???)

To me SRXs are the best sound libraries available in hardware; you can find a lot of high quality sounds and loops that you can use with G-70, but only you can judge if they worth that money, once again according to your taste and needings.

Quote:
Originally posted by hellboy44:
3. Finally, with all the talk of the extensive EQ editing and amazing FX on board the G70 now, does it REALLY let you change the sounds to individualise the keyboard in a meaningful way?? - I always thought EQ can be a disguise for a bad sound in the first place...

Yes, there is a lot of possibilities in customizing sounds using the single tone and drum sound equalizer.
About MFX, please note that on G-70 you have only one available for realtime parts and you can use another one for song/style parts applying a special trick (routing part to external input MFX via direct outputs).
On E-80 you could have 3 MFXs available for song/style parts but, as you know, only 61 keys.
If EQ and MFX improve or damage the sound quality it depends mainly on how they are used.