Done.

I haven't gotten to advanced synthesis in Sophie, but it's quite different and rather fun to mess around with. It's really a fantastic direction for synthesis to go in. Its battle system is the part that needs improvement. It doesn't match up to E&L or Shallie, and probably not Meruru either. I'd call Meruru the more fun of the two, for its overall polish, battle system, as well as the structure. Sophie's structure is a bit of a mixed bag in that it lets you do what you want most of the time, but it's purely about unlocking and making items with nothing thrown in to spice things up. Basically, it lacks a sense of purpose and it doesn't really ask you to do anything outside of what you'd already be doing.

I did not play Meruru+. I only double dipped on Totori and E&L for guide writing purposes... and Rorona because it was a remake.

Also, if you think it's hard to beat Meruru... some people will tell you Meruru is the best game in the series but I feel strongly that E&L and Shallie are better.

That's a bit of a tough one. Sophie has more polished gameplay and a throwaway story from the good chunk I've played. Ayesha's gameplay is a step down from Meruru's but everything else about it is great. You could easily go for either depending on your preferences.

If you're interested in the entire series you might as well go in order. I'd otherwise give a slight edge to Ayesha.