First, let me say that I like TMB very much.  It is nice, much more profitable then LTC.  Also I have little experience with middlecoin and may just hit bad times, but it was much less profitable then TMB too.

But still , lets try to understand what is going on with reject rates, that is quite hight for me and some other users.  Here is what I have found in this thread:

me 10% (europe)
Sinyk7 ~10%
MagicOnline 10%
interupted 10%
kudrya 8-11% (europe)
machasm 10%
ktworld 8% to 9%
nickdmj 8 and 15%
lejboua 10-13% (europe)
fanyinan2008 10% (china)
bullus 5-7%
FABFAB 6% (europe)

Any ideas?  

Has it smth to do with location? Too little data - can you you provide your location to check it?