I made the switch to Android when I retired my iPhone 3GS, the money Apple were after for the iPhone 4 was just eye-watering. (I can't honestly remember how I ended up with the 3GS, must have bought it second hand or something, but in typical Apple fashion they'd released a version of iOS that ran on the 3GS but turned the whole phone into a juddery lump of shit.)
My initial thoughts with Android at the time were that it was a bit rough around the edges (obviously you're going back a few years), but I saved a decent chunk of cash moving to an Android phone that had all the functionality (and more!) of my old 3GS, and ran a lot better too. (Think it was a HTC Desire, as memory serves it got me a WiFi hotspot which iOS didn't have at the time.)
Since then Android has got better and better, and if you stick to a vanilla Android phone you get the 'unblemished' Lollipop which is a great UI and every bit as lovely as iOS IMO. Your mileage may vary with the various manufacturer customisations (personally speaking I abhor what Samsung does to their phones, but I think Sony's UI is actually pretty good - for example).
IMO they've lost the plot a bit with the Nexus 6 though, which is stupidly big and stupidly expensive, but there is talk of a 'Nexus 5 2015' model on the way which would be very interesting. (I'm currently on a Nexus 5 which on balance I'd say is the best phone I've ever owned and very reasonably priced.)
All that said I wouldn't necessarily rule out moving back to an iPhone at some point, but every time my contract comes up for renewal I look at the prices for iPhones, and then I look at the prices for good Android phones, and I'm just like, 'Yeah, fuck that'. (IIRC when I got the Nexus 5 I could get it 'free' on a £35 per month contract, whereas the cheapest iPhone was something like £240 cash upfront on top of the £35 per month. PLEASE NOTE - we pay crazy prices for mobile phones on the Isle of Man.)
If you're not particularly tied to the 'Apple Ecosystem' (loads of apps, big iTunes library etc, and by all accounts you're not), then the switch should be very painless.
Android does seem to make stuff that SHOULD be simple, nice and simple, for example Mrs Hearthly wanted a basic and easy to use media player on her Moto G 2, so I just installed VLC (free) from the Play Store and she can drag and drop stuff from folders on her PC to it. The last time I tussled with a simple task like that on an iPod I ended up in a
murderous killrage. (Seriously fuck iTunes.)
I suppose the thing to do is just an Android phone a try, end of the day if you really don't like it you can move back to Apple at your next switch. But your use of your phone sounds very similar to mine TBH (not much in the way of apps, want decent camera functionality, etc), so I think you'd be fine.
Having had a quick look at prices the Z3 Compact costs a fair whack less than the iPhone6 too, so you've got a decent wedge of cash to spend on something else straight out of the gate.