Overall Thomsonfly is a career choice. It is not a low fare airline despite what the 737 fleet started out as. Nor does it have a lifestyle a la Easyjet. You will not be flying out of base all the time, so there is some hotelling involved.
You may be able to request to do this later in the summer, or indeed fly out of base if you so wish, with the new rostering system under development. The more seniority you have the better your chances of you preferences for you roster choices being accepted.
Choice of fleets does not really matter these days to lifestyle as from this summer the route network on shorthaul will be similar on the 737 and 757.
Think Greece Egypt, Turkey Canaries etc more than Paris, Amsterdam the tide is turning back to traditional charter routes on the 737.
Obviously captaincy much quicker on 737 than 75/67. If a low time FO think 4 years to get to the minimum hours, and then be well above average as well!
But do remember it is a career airline, even if it takes 14 years as it used to, well worth the wait IMHO.
However basic pay not great, the package overall is good. It could be better but where couldn't??
Not many people leave that must say something..