In reply to Tom Ripley Mountain Guide:
Had two XGK's for twenty years (shaker and pre-shaker versions) and have replaced with an Omnifuel for the past 3 or 4 years. Overall I think the omnifuel is better. However this may be becuase I'm burning cleaner fuel in the omnifuel.
One thing to consider is that if you are going overseas, particularly himalaya's or N. America, should you have a stove problem you will have a much greater chance of finding spares for an MSR than a primus.
Note also I don't think MSR fuel bottles 'mate' that well with the primus pump. I know many people do without issue, but I only use a Primus bottle, and if taking additional fuel in my old MSR bottles always decant into the primus bottle.
Other thing to note is that due to the connection design you need to depressurise the primus bottle, before disconnecting the stove.