easySwiss is a good place to work, with good perks good salaries, FO's make a UK capt salary but bear in mind that life is Switzerland is expensive. So let's say that you make good money depending on where you decide to settle down. Expect about 7500.-CHF take home (after all taxes, incl. income tax)
Random roster, there are talks going on about a fixed roster, but it takes time to be sorted out. You could end up with a block of 2 days off in month max and a block of 4 days off min. FTL's aren't as restrictive as in the UK, so you fly more, especially on early shifts.
No busy/quiet season for GVA, the only 'cool' month in the year is November. You do fly a hell of a lot all year round. Different in BSL, but it tends to change, used to be quieter.
About the ppl, in BSL there are a lot of swiss german guys or german speaking guys, but they have a very good english. in GVA, being in the french speaking part of Switzerland, lots of french speaking guys.
If you hope going back to the UK/rest of Europe in the future, don't go to EZS, you'll NEVER be allowed to transfer back to easy UK (nobody has been allowed a transfer in the last 10 years). So many ppl got stuck down there and had to resign to go back to the UK.