I recently added the Studio SRX board to my G70..and I must say..I love it..

Over the years I have been a big fan of Roland's expansion boards...going back to the JV series..

Roland knows how to sample and develop these boards...The vast majority being excellent..They all score in quality sound...

I also thought as Diki, that the G70 can live on it's internal sounds...and that is true....but the Studio board added some great sounds..that are some of my go to sounds now...Some of the electric pianos are SUPER...one reminds me of the MKS20 tremolo EP..
I have found 3 EP's that I use now...

There are a couple acoustic pianos that cut thru any mix...

The saxes for the most part...I find more usable than the stock saxes..not to say the saxes on the G70 are bad....The studio guitars are also excellent..

Some of the basses are now my go to choices..

Brass selection are also better than the stock G70..

I am glad I tried the Studio board....There are only 128 patches plus drums, divided into the 64 meg board..Other boards have as many as 300 plus patches in the same 64 megs..

I now wish the G70 had more slots..(my 5080 had 8 slots)..I believe I would load it up..

A neat thing the G70 does...it puts the sounds in the proper instrument groups..(placed at the latter pages) with EXP icon..

As an example..if you open the Electric Piano group ..the new EXP EP's reside on the last pages..

The EXP board sounds are able to use in styles and sequences too..

I have owned most of the JV-80 boards and maybe 5 SRX boards...None have disappointed me...although there were many sounds I was not interested in...but they did sound good too....