i think it's still a good buy, especially now (prices are low if you look around a bit), with the right custom rom and kernel you have a snappy device with latest functions
i'm definitly not updating... don't care about security... only a working phone is what i care about
i've never heard of anyone that got into trouble because of those 'security risks'
don't throw it to the wall yet, try a custom rom first. i'm using a rom with fire-ice kernel and since then no more freezes... snappy as hell... it gave my nexus a second life
not hard, just look for a video on youtube
be careful around camera, you won't break it but might loosen the camera, and putting that back means more work