Agreed, I've used magnets across brands. The only difference is strength, there's no magic Cateye magnetism. Once when all I had to use was a cheap generic WalMart magnet, I couldn't get it close enough to trigger, so I epoxied on a neodynium disc magnet, which made it probably twice as powerful as the original, and it worked fine for a year or so until I bought a new base, which also came with a new magnet.

Sometimes the magnet has to be really close. Move it until it's actually touching then back it off a little. It may also help to put the sensor and magnet as close to the hub as possible; this makes the magnet move past the sensor much more slowly and increases the odds of consistent performance. It also unbalances the wheel less.