Try FreeIPA, it has good support through mailing list. The actual people working on redhat support is giving solution through mailing list. when it comes to IPA from Redhat, they are bit laggy and freeIPA is releasing and fixing the bugs frequently.
we had a installation of FreeIPA with morethan 1500 clients.
if you want to try another products, you can try centrify. free version is limited to 200 clients i think. but very good product.
another option os
powerbroker . seems like they are paid now, before the product name was something different and i saw people acieved AD autentication with that old product.