Just watched Star Trek The Next Generation for the first time! Loved most of it...though it has some middling and really bad moments. About to watch all the TNG movies next!
I watched the pilot episode...it was hard going from HD TNG to SD DS9. Maybe some time off and I'll come back to it and not notice the quality difference!
For both series, the first 2 seasons are kinda rough. Once they figured out what worked they really start to shine from S3 onward. Personally I hated the whole Bajoran arc on early DS9.