I think people who go straight onto jets do miss out by not flying a turboprop as it is good fun and lots of hands on flying. A turboprop is a lot more forgiving than a jet and you can do things like come down the glide slope at 240kts until 4 miles and still slow down in time to land. In a jet you are starting to reduce the speed with 20 miles to go.
Don't listen to people who say jets are harder and more complicated than turboprops, these are usually the people who haven't flown a turboprop and think they are just a big Seneca. I have flown the ATR and the 757 and the ATR was more complicated and harder to fly!
The main thing when chooseing a jet or a turbo (if you are lucky enough to do so) is that jet time is more useful when looking for your next job or if you are made redundant. Believe me more than half of the pilots you talk to have been made redundant, myself included. Jet time will get your CV noticed quicker than turboprop time.
At the end of the day this is just a job and it is a job you need to do to pay the bills. If you find yourself out of work, you need to find a new job quickly as you could loose your house! Jet time will give you more security but you will miss out on the hands on fun of the turbo prop. It is great to hear enthusisiatic guys out there just about start there training, saying they don't care what they fly and it's all about the flying that matters, but if you can try to plan your career, if could pay off in the long run.
I know I sound like an old man who has grown tired of the industry. I have just experienced alot of change and disruption. By the way I have only been in the industry for 3 and a half years!
The overriding factor in any desicion though is which job starts first! You may turn down the turbo prop to fly the jet, but the course doesn't start for another two months. In that time the airline may merge or find there requirments change and suddenly where you had two jobs, you now have none!
Enjoy the job, it's great when your in the air!