I was a diehard fan and I own every season. Mind you I caught it after it was off the air in reruns. I think the first 3 seasons are some of my favorite television ever made. No show has ever grabbed me like Season 1 of the X-Files. I didn't really care about the Mulder/Scully situation one way or another. What really grabbed me about the show was Mulder's quest to find his sister and the alien conspiracy which I felt was set up really well early on and then turned into a convoluted mess that never resolved to my satisfaction. Easily my favorite sci-fi series of all time and one of my favorite shows of all time period but it definitely had some serious flaws as well as strengths.
I actually thought the Smoking Man was handled okay but everything else about the Conspiracy ended up being too convoluted and sometimes just bad. The movie I have mixed feelings about. It felt like an end to the show but then the show just...kept going and they had to find a new alien plotline which seemed to have potential beginning with Season 7 but that too was botched IMO.