Hi Sweetpea I hope that I can help you a little here ...
The answer to your question lies in what you are looking for! The difference between the Canary Islands is large and even within those islands the resorts and areas majorly differ. However compared to the mainland you will find a much better year round climate with average temperature on most islands 21c even in January (today it's 28c in our back garden).
I can give you a good idea of Lanzarote but not living in the other islands it would be unfair of me to give an accurate guide ... although wikipedia is always a good place to start.
Property prices do vary from island and resort however it is important to think about location, development and infrastructure ... as finding a nice place on one of the islands with no telephone lines, no local shops and bars and with big development around you might save you some cash but maybe not your sanity.
When I first decided which island to live on I visited them and visited the resorts, the answer then came easy to me as I fell in love with Playa Blanca, which is in the south of Lanzarote ... modern resort, good infrastructure (we're even getting a bus service), good school, nice local community (expats & Canarians), limited development boundaries, quiet natural beaches (Papagayo) etc. etc. I wasn't so worried about the greenery (it is only 20 euros to fly from Lanzarote to Tenerife anyway)
(SNIP)I hope some other islanders give you an insight in to their islands as well!
Good luck and I hope like many of us you find your perfect location to settle!
Phil