401k Transfer?

No reason to unless the available funds and expenses aren’t as good as the current plan.

Probably depends on if you also want to have another account to manage. I am moving my 401k to my new employer

I like having everything in one place so I rolled over my previous employers 401k to MSFT , you could also roll it into a traditional IRA but then you’d have to start managing it

When changing jobs, I always "rollover" my existing 401k into a "Rollover/Traditiinal IRA" in a well known financial institution. That way I can invest in whatever I want (within the guidelines of IRA rules, of course). Although 401k's generally have a good variety of choices to invest in, they are always limited. A Rollover IRA at any of the top 10 investment firms will have all the investment choices of any 401k, plus it will have many many more vehichles you can also put your money into. Remember, however, that a Rollover IRA is managed by you and you alone (unless you have a financial advisor), so dont invest in anything crazy, this is supposed to be your nest egg. I am fairly young and dont want to spend a bunch of time investing, so I just throw, everything into a S&P 500 equivalent. I could do this within a 401k, but in an IRA, i at least have more choices and if I change my mind and want to be more active, I can do so.

I think if you do the traditional IRA you can’t do the backdoor roth ... emphasis on “think”

Depends on if rolling over you will invest the IRA properly imo

Keep in mind that if you ever go bankrupt. A 401K is considered a pension plan. An IRA is considered a savings vehicle. The Bankruptcy Court will take your IRA money, but not your 401K.