I"ll say this for Rise: It didn't just lean on nostalgia. The majority of villains, side characters, and plots were wholly original, and mostly memorable. Unfortunately, that might have worked against them, especially waiting so long to get the Shredder in there, but still, this show really tried to be original.
And that finale is AMAZING! I still say, if the show isn't grabbing you, you can still skip ahead to the last 3 half-hour episodes and have a good time. I think this is a solid-enough show with a real banger of a finale. And, yeah, I want to see what they cook up for the movie, too.
Meanwhile, I just read the Odyssey and Origin fan-comics that attempt to wrap up the Mirage universe. Mirage is WEIRD, guys! And, no, I still haven't read through Mirage proper, so I'm doing this out of order but...Mirage really went off the rails at some point, didn't it?
I actually recommend Odyssey if you like Multiversal Turtles Forever-style hijinks in your comic books. It's actually a interesting read, and I think you can follow along if you've seen the 2003 series (and maybe read a few entries on TMNT Entity).
Origin...kind of deals with some odd side space and cosmic stuff that I only partially followed. They mention 3 or 4 Utrom factions...for starters, even though they don't come into play in the story very much. Origin does have a prequel for Odyssey included (and a fight against the Predator...for some reason). If you track down both I'd still say to read Odyssey first.