Hi Andywelder
(and anyone else who owns a SIP MIGMate with a good grip on electronics)...
When I did my 'net research on which small MIG to buy, I was considering the SIP MIGMate 150 and came across a guy's web page where he posted info about improving the wire feed controller in his SIP MIGMate 150 by replacing a variable reisistor in the controller circuit.
If you are not satisfied with the wire feed and you are fortunate enough to understand electronics enough, it might be an option to try out (well, at least before giving up on the welder and buying a new one)