Cheap KVMs = sh*t.
Bought one from ebay and while its "adequate" it just fails to meet the standard of a decent BELKIN one.
Cons: Flickers with high speed video, faded colours/ghosting, also if a phone goes off near it, it turns to sh*te.
Pros: they cost £8 on ebay, and they work, sort of.
There is a shame I dont believe there is anything like this product for linux, as well I used to use this quite a bit.
http://www.maxivista.com/Actually thinking about it, just use VNC. Simple.