I used to use GA 2 and 3 a while back. I thought I’d get back to that so I upgraded my GA3 to version 4 in the sale. I did get Metro Heights and Songwriters add-ons, and was wanting to know between Nashville and Simon Phillips which one would you suggest to be the most versatile (and not more or less the same) to what is already included in GA4 plus what I have? Thanks.
Both sound great, but the Simon Phillips Studio Drums is by far the most versatile of all acoustic expansions for Groove Agent 4.
It includes a ton of different snares, toms and cymbals, and on top of that there are several dozens of “trigger” samples that can be layered with the regular acoustic snares and kicks. All of this helps the kit work really well in many different genres.
Interesting… I both like Metro Heights and Songwriter. What keeps me from trying Phillips was the sheer amount of drums. The other two are reduced sets and Phillips looks to me like having three drummers at once 
Personally I’m more looking at the Nashville set. But I don’t own it (yet), but for my taste it looks more reduced than that overwhelming 80’s style Phillips setup (which I don’t own either, so that’s probably a not very helpful comment on this topic).