Airwalker, FMS is an OK breeder. Better then most fem companies and are active on another forum that even have their own section for testers etc. Most of their stuff is average if you ask me, but have only grown 3-4 things from them. By average I don't mean bad, I just mean like you would expect from most good fem seeds. The C99 is easily the best strain they have in my opinion and probably everyone elses. C99 is just one of those strains that is hard to mess up... but somehow G13 labs did. Most of the C99 seeds you see today are like F4-F6 generation so they are pretty inbred lines. Usually chosen for the best characteristics so won't have as much variety, and each breeders will be slightly different for this reason. The original C99 from Bros Grimm would have had all of these plus many many more phenos, some average, some stellar.
Something else I have noticed, almost everyone that posts pics of C99 that did not grow them from FMS seems to have average sized leafs. All of the ones I have seen from FMS has super razor thin leaves, and so did mine. Like as thin as leaves as possible for cannabis plants because any thinner and it wouldn't be a leaf. I know they have that certain pineapple pheno dialed in pretty well but it's just crazy that I don't see that thin leaf structure on more peoples C99's. I wonder how rare the pheno that FMS uses was in the original Brothers Grimm seeds.
Also, Airwalker.. to answer your question if you are looking for antoher plant to grow out from FMS I would recommend PURE AK. It isn't anything super special but it is another one that I had good results with. Well I should say average results overall because I planted 2 of them, got 1 that was super indica very huge leafs, stout close internodes very weird mutant plant. It is the only plant I have ever killed instead of flowering out because it was just all messed up. The other one was the complete opposite, extremely sativa with thin razor leafs like the C99 has.. grew much like C99 but more sturdy. Huge yield, very frosty buds and one of the best plants I ever grew from Fems. To this day, I have never ever seen another AK47 phenotype with those razor thin leafs but it was deff good stuff if anyone can find it. If I knew I could find that phenotype again I'd probably pick up a couple, but I bet it'd take 100 beans to find it again. Could be wrong though.