Having been flying military, microlights, light aircraft, and anything else I can get my hands on since I was about 18, I've no problem with the safety of a flexwing. Statistically they're pretty much as likely or unlikely to kill you as any other class of light aeroplane - around once every 50,000 hours - with virtually no structural failures, it's the usual collection of take-off and landing accidents, trees, powerlines, and the occasional mid-air.
If you're used to big jets with conventional controls, you'll find it a steeper learning curve than perhaps you anticipate, but that's just part of the challenge. They are incredibly cheap to buy and run (if you want them to be), and I can't honestly think of anything I'd rather be flying locally on a fine summers evening than a flexwing.
If you want actual running costs, £3k+ will get you a reasonable low performance 2-seater (obviously you can pay a lot more, and will get a lot more aeroplane, but that's a reasonable baseline), and £1000pa should get you around 40-50 hours of recreational flying.
Your £3k aeroplane will probably cruise around 40-50kn, need about 200m of runway, and have about 150nm legs.
And, as bose says, it's worth joining the BMAA for the help you'll get (you'll need to to operate the aeroplane anyway).
G
200ish hours on flexwings.