Super Smash bros was much, much more enjoyable than Melee. Still is, I think... but I can never find anyone willing to play it with me anymore.
Now I will tell you why.
First, and most obviously, Super Smash bros came first. It featured a brand new type of gameplay, never seen before, and it was pulled off wonderfully.
SSBM featured the same type of gameplay, but the impact of it's innovation was no longer there. This only applies to people who played the original back when it came out, of course.
Second, the level design. Super Smash Bros had far better level design than Melee. Every arena in the original had it's own quirks, it's own tricks to get used to. Melee... well, the levels are not quite as good, plain and simple. There is nothing in Melee which can compete with the old Mario Bros stage, with the floating bumper. Melee's version of Zebes is not nearly as good as the original's. Melee's version of Sector Z is smaller and altogether less enjoyable than the original's.
On top of that, in the original every level had a unique and interesting hazard. Mario stage had that bumper and the moving platform on the bottom. Zebes had the lava. Hyrule Castle had the whirlwinds. Saffron city had those pokemon that burst out of the door. The classic Mario Bros stage had the tubes, pirahna plants, and pow blocks. Etc., etc. In Melee, only about half of the levels have hazards like that, and a lot of them are basically the same thing - a moving level. Not as good.
The gameplay, though it may seem the same, was different enough to make the original a far better experience, in my mind. Melee is faster paced, but in a worse way. In the original, dodging took a bit of skill, but was far more important to do and far more satisfying to pull off. Getting hit actually mattered - in Melee, you'll get hit, take damage, but it doesn't really effect the overall game as much. In the original, items like the Beamsword, Homerun bat, and bomb-ombs were actually important pieces of the game. They are less so, in Melee.
That said, I wouldn't really say that the original is the better game.. just that I enjoyed it more.