From an ATPL issue point of view, ICAO/JAA/CAA require the candidate to have requisite flying experience and an acceptable medical standard, together with demonstrated levels of skill and knowledge. The ex-service pilot will have the relevant experience after a few years on a squadron and will probably have no problems with the Class 1 medical, having been similarly screened for military flying. Service pilots with recent currency are granted certain exemptions from some exams and are only required to be flight tested for the Instrument Rating. (I think I'm right here but if things have changed recently, no doubt someone will correct me).
As far as helping with that all important first airline job, it depends very much on supply and demand. If jobs are tight, pilots with "heavy" time are obviously best placed but in the pilot shortage situation we had not so long ago - yes, really! - even helicopter pilots were being taken straight on to jets. I don't really see any prejudice against fast jet pilots. A (very) few single seat guys have a bit of an adjustment problem but most soon revert to being mortals like the rest.
Airlines have training budgets so they are always seeking to minimise training risks (candidates failing to make the grade). Because of this, someone who has come through the military training system with its ethos of meeting a high standard or being washed out is probably considered a better bet than a straight through civil wannabe. It may not be fair, but that's how it is.
confundemus