depends on whether you looking for short term gain or long term career..if you're looking at earning loads of $$ at young age then i would suggest that you go for the service companies.

bear in mind though, looking at the job scope of field engineers in service companies which is totally unrelated to what design consultants are doing..most likely the design consultants will not consider you if you decide to quit from services after 2-3 years. Even if they do consider your application, most likely you will have to start from zero (like a fresh grad) and i'm 101% sure that they will not give your last drawn salary at the service comps..in other words, prepare for a serious pay cut.