There are important differences between the Magnet and Clutch...
1) The main difference in feel is the inside rim depth, the Magnet rim feels much deeper than the Clutch. For my fingers, I can simply never get a clean release with a deep rim, my fingers get hung up on the edge. So I use the Clutch, since the feel of a good clean release is by far the very most important factor for my putting success.
2) The main difference in flight is glide, the Magnet has more glide than a clutch. If you lob a Magnet very softly underhand, it will usually stay up in the air longer, even at short ranges. The Clutch requires a little more spring action in your fingers, wrist, and/or elbow. Personally, I putt better when I release it with intent, aiming to pop it through the center of the chains. Also, glide can be good or bad, depending on your putting style. A glidey putter (e.g., Magnet) is prone to running off way past the basket on misses, whereas a putter with moderate glide (Clutch) will settle down more quickly.
There is little difference in stability, probably because the outside nose profiles are so similar. You can find more and less stable Magnets in the many varieties of runs that have been produced, so you can definitely find some that are exactly like the Clutch.
The Clutch would probably have a slightly higher speed rating, since it shines at slightly faster speeds than the Magnet.
The Clutch pushes through hyzer very well, it takes a couple seconds for the disc to start moving left, even on an extreme hyzer angle. You can get it to move left sooner by lifting the nose more, but you have to lift it more than you would the Magnet. This is related to glide.
I like the Clutch better in wind than the Magnet. The more glide a disc has, the more prone it is to being carried off in wind currents. So the Clutch requires relatively less compensation in the wind than the Magnet. This is again related to the glide.
The Clutch is great for spin putting, dart-throw-type putting, hyzer putting, and wind putting. And better for small hands.
The Magnet is much better for touch putting, lob or loft style putting, or generally soft glidey style putts. And better for large hands.
Anyways, putting is so personal and stylized, I'm certain almost nobody will have a similar assessment. This is my impression, after 5 years experience with Magnets of all varieties, and using the Clutch as my putter of choice after getting a 1st run early this year.
The story has been told here many times, but the idea was that Steve Rico wanted to make a putter more like the 1st run Magnet, and came up with the Clutch. Discraft doesn't make any like the 1st run any longer, and they are so hard to find that I won't ever be able to assess how successful he was in his attempt.
I think I can say quite confidently that Steve Rico is the all-time greatest master of the Magnet. Nobody throws it better. On the other hand, very few people can throw a Magnet like he does, so it isn't clear that what is good for him will carry the same benefit for us mere mortals.
Distance Drivers: Barsby Boatman, Glow Champion Katana
Fairway Drivers: Pinnacle Rival, Icon Patriot, Protege Rival, Elite-X Cyclone
Mid-Range: Ghost/Wasp, Z Buzzz/DGA Squall, Z Glide
Putt/Approach: Star Classic Roc, Icon Clutch, Protege Clutch