Yes, Rock Band is my favorite game series.
I played a ton of Guitar Hero 3, 4 & 5 but Rock Band eventually earned my loyalty because almost everything would import into the next game. Guitar Hero was extremely hit or miss with which songs would be able to be carried forward.
I keep Rock Band 4 installed and have a library of 1600+ songs still growing, I will buy any of the weekly songs if I like them (which admittedly is less and less often). I have the adaptors that let me plug in my e-kit so I can practice drumming on the real deal in Expert Pro mode. The undisputed king of party games imo.
Rock Band 3 is probably the best the genre ever saw, but 4 has been good enough to keep the flame alive. I really hope they end up making a fifth for the current gen of hardware so we can get some QOL improvements.
I have imported Rock Band 1, 2, 3, Lego, Blitz, Green Day, Track Pack Vol. 2 & the Classic Rock Track Pack into 4, and at this point, I am there day 1 for anything Rock Band related that they release (I also got an Oculus Rift for Rock Band VR which was really cool! It's a shame it can't be played on any of the newer headsets).