Well I have a Terminal Mix 4, but this is a considerably more expensive controller than the beatmix. But so far the controller was flawless and the reloop support in general very helpful and friendly.
Also I have been on the road with the unit a lot and just threw it in a bag, never had a problem.
The Beatmix is lower priced, but I have not heard bad things about it so far. There have been some problems with older reloop models (early mixage and early jockey) which had some production problems, but to my knowledge they were replaced under warranty.