Hey,
I have just started working for Oasis but as a float nurse- So i basically travel around my local area and cover sickness/days off- a bit like a locum but i am actually employed by them and have a contract etc. So far i am loving it!! For me the pay is good. I have a few friends who work/worked for oasis and its mixed reviews- same with the pay mixed....however your current employer should have a contract when selling to oasis and they should honour your rate of pay as it is now.
With any corporate there are pros and cons. The biggest thing is for everyone to have a positive attitude during the transition and not write them off straight away. Things will change as they will have their own procedures. If you have a good team then the family feel should stay
Good luck xxx