Yamaha DTXpress/DTXplorer/DTXtreme

Well ive been looking around everywhere for info about good and 
somewhat cheap double pedals... when i bought my dtxpress i bought a 
not so good single pedal with it... (millenium) so i have to upgrade 
that no matter what. so i was thinking about buying a double pedal 
because it would be fun to learn double bass. The thing is i dont 
want to buy some shitty stuff like the single pedal i own now... i 
will certainly regret it later. So i looked around the net to find 
info and it seems that everyone is praising the tama iron cobra. 

Anyone tried it who have have played on some other double pedal 
before ? would be interresting to hear if it as good as they say.
I saw a iron cobra jr too it seems that it is a cheaper iron cobra 
model? anyone tried that :)...... btw i saw a third interresting 
pedal,a weird looking sonor pedal 
  
http://www.netzmarkt.de/thomann/thoiw5_artikel-153282.html
that one is quite cheap so i guess you know what the next question 
will be :=)
anyone tried that one?

Andreas