Hi hotel hopper,
Yes it's a fairly good place to work (certainly no worse than a lot of others from what I hear). The smaller bases definitely have a pleasant atmosphere. Giving you an idea of the likelyhood of getting a specific base is next to impossible I'm afraid. The main thing is that smaller bases tend to have less movements, so you'll probably wait longer for, say, EDI than LGW.
I would imagine with 4 years on the bus, plus some long haul, you'd get a command within a year or two if your initial sim checks go well.
P