The wife and I have been reminiscing a lot about the X-Men cartoon since I've been getting back into comics.  We both enjoyed it when we were young and noticed the discs were all on Netflix so we'd go ahead and watch it.  (It's also available on Marvel's website, but good luck navigating that in a non-annoying way)  I'm surprised that the writing holds up well.  First of all, we saw it as kids.  So of course we're going to idolize it in our heads.  Second, it was the 1990s.  Thankfully there isn't too much "tubular" and "phat" and stuff like that.  (A little bit from Jubilee)   There is a little bit of hokeyness here and there, but it's a super hero kids cartoon.  There's going to be some of that.  Still, I think it works because it talks to kids like they're smart.  
 
The voice acting is a little uneven.  I find that Wolverine, Jean, Beast, and Gambit have the most natural sounding voices.  Beast is actually perfect.  Professor X and Storm are OK.   Cyclops sounds a little too much "Hey, I'm the leader of this team" and Magneto's accent is a bit off.  I think that has to do with his origin change, but I'll get to that in a minute. 
 
Overall, there's only one thing that did not age well about this cartoon - the animation.  This cartoon was made during the time of the Animation Age Ghetto and it shows.  The frame-rate is horrible.  It's like watching Anime, except that with anime, they know they can't have as fluid movement so they take steps to make it look good within their limitations.  Sometimes watching X-Men is cringe-worthy!

This disc contains the first eight episodes.  They introduce Senator Kelley, The Sentinels, Magneto, Genosha, Juggernaut, The Morlocks, and Colossus.  (And an off-scren mention of Moira McTaggert) It's pretty neat how well they actually stuck to the accepted comic book canon.   They made some changes, though.  While the first time they face off with Magneto is pretty close to the actual comics - takes place on a military base and everything - the lineup is wrong.  Rogue is shown as already being part of the X-Men.  In reality she was in the Brotherhood of Mutants first.  That one's not too bad.  Also, Beast should have been there (and without blue hair).  Again, it's not a biggie.  
 
A much bigger change was making Magneto be from some random east European country that was overrun rather than a victim of the Holocaust.  Of course, I totally understand why that's not appropriate for a Saturday Morning Cartoon.  But it is a pretty major change that gives him more of a grey morality than as black and white as it seems in the cartoon.  So it's not too bad.
 
I'm sure there are other errors, but the only other major one I saw was Cable.  I'm not sure if this gets resolved in a future episode, but he doesn't have his cybernetic arm.  And there's no mention of Cyclops being his father.  That one doesn't make too much sense, but, again, maybe they'll get to it later.
 
In conclusion: having seen the first disc, I think, so far, the series holds up to the test of time and age rather well. (except for the GIANT cell phone that Jubilee wields)

This is the best cartoon based on Marvel comics ever. Loved it, love it even more now. It never gets old. It is such a smart show and the characters come to life like no other show has been able to do for our beloved mutants.

It's awesome.  I also have fond memories of the Spider-Man cartoon.  Maybe that'll be next for us.