And it will help you - how - to now go somewhere else where once you get a class date you are still going to do another 3-4 months of training? The most reasonable thing to do is to finish what you have almost completed before starting over.

You need to finish up, get your type rating and consolidation at a minimum, otherwise you get no return whatever on your investment and have to repay your bonus. Better yet would be to go through your probationary year. If you don’t like it once you get on the line, start interviewing after 6 months and line up the first class available after you have completed probation. With an ATP, a type rating, and a year of 121 SIC any regional will fall all over themselves to get you and generally give you ANOTHER new hire bonus and a type rating bonus as well.

Understood but a future potential (major) employer will look at ANY departure from an airline in under one year with suspicion. They'll be concerned you got fired/resigned in lieu of termination while on probation.

If you had a good reason, you might be able to explain it away, but if possible better just to avoid that conversation altogether.

You're crazy. Im from BOS myself, and went to an airline without a BOS base, but I'm not gonna go through training again just to be a junior guy again, and get boned time and time again on reserve for another regional airline.

Plus it wouldn't look good on the resume.

Also keep in mind bases open and close, so who knows how long BOS will be open for them.

Agreed. When I look at resumes moving from one job to another in less than a year sticks out like a sore thumb. To me, that means you were unable to complete your probation for any number of reasons.

I call them "job jumpers" and their resume usually ends up in the round file.

Thousands of pilots have left regionals in less then a year and moved on. Often MIL pilots don't even complete six months.
Are these job jumpers screwing themselves by taking advantage of a better opportunities?
If he's at Express Jet (sounds like it) it's a dumpster fire with no relief in site. Moving to a much larger and stable airline like Republic would be understandable.

The MIL pilots likely not. Most of them are moving on to their final employer in any event. But they are and have always been a special case, especially the non current retirees who flew a desk th3ir last tour or two and needed to get recurrent.

But the rest? Yeah, oftentimes they are. That doesn't mean that many of them won’t make it to their career destination eventually anyway, but leaving while on probation is seldom a positive for career advancement - unless like the MIL guys your next jump IS your last.

Definitely finish training and then do what’s best for your QOL/family.

I would recommend spending some time (a year or so) out on the line before making any big decisions like that. It will go by quick and you may discover that your first choice was the right choice. Sometimes it's hard to judge a company by their training department. At my operation, it was like two different worlds. I'm really glad I stuck with it and didn't try to jump ship because things seemed like a cluster f* in the beginning.

FWIW, BOS is super junior at Republic, both on the CA and FO sides. In fact, the most junior CA award went to an Aug. 2018 hire. Who knows if it will stay that way... just wanted to throw that info out there for your consideration.

Comparing MIL pilots to non-mil pilot in terms of jumping is comparing apples to oranges.