I'd echo whats been said before.....It's all about money and perception.
A turboprop engine I would imagine, is harder to operate than a pure jet - look at all them levers. The RB211s on the 75 are simple.
No, it's not about 'engines' - what they are saying is you have only flown something light and slow, will you convert easily enough.
Personally , if I wa sunder 30 I'd have a bash at the TP command as good experience and fun, if something of a dead end.
Over 30, I'd go for the jet FO - assuming this 'jet' is a useful type in it's own right.