I completed Rayman 1
yesterday. Good game and not the easiest one. It can be frustrating and it is quite often unfair, trying to screw player and force him into repeating levels. But it never made me hate it and want me to abandon it which sometimes happens with frustrating games. It is certainly old and it shows, both in mechanics (you've got lives and if you loses them you are done; it is quite easy to gain more though) and in graphics. It is pixelated and not the best looking one anymore. It still has certain charm and are nothing to be disgusted about. Also sometimes it is somewhat arbitrary in what works and what doesn't but it is not frequent thing.
What I love about the game is how cheerful it is. That's gimmick of all Rayman games and this one does it well. It constantly feels like joyous adventure and Rayman seems to enjoy everything he does and even if it may sound bit childish, it made me enjoy everything as well.
I had almost no technical issues with it and even 360 controller worked just fine out of box, except for troubles with crawling and with need to calibrate it every time I ran the game (without it it wasn't as precise but worked).
I prefer Origins over this one but I liked it and would rate it as high as 8/10
If you don't mind older cheerful graphics and hard platformer, you shouldn't be too afraid to try this one. Full list.