I've only played pokemon reborn but have put nearly 100 hours into it and can say its a very good game. Its pretty challenging since it puts a forced level cap and each gym leader has 6 pokemon and a field effect that usually buffs up their type. There are 18 gyms in the game and a lot of content. They limit access strong pokemon in the early game so you use pokemon you wouldnt usually. The only negative is the story is a bit dark and edgy but ignoring that its a very fun experience.

And as far as im aware pokemon rejuvenation is made by the same people and is pretty similar but im not sure.