I've got one, although I'll probably move up to something else eventually.
But as an all-grain job, it's great and cheap, although as above, the 35 litre one was £148 this time last year - there are often codes hanging about (I can't remember what code I used).
I think it's unfair to call it simply a boiler. One of the downsides is that it doesn't have a pump, although you'll be looking at models twice the price (unless as above, you can find something secondhand). I don't find it difficult though to simply use a jug every now and then and rinse the mash.
I'm also lucky enough to have an Aldi urn and I simply set it to 70c to rinse at the end.
It does have a cooler, although you have to work out how to connect it to either a tap or in my case, a hosepipe.
I find it perfectly acceptable. It does take a bit of getting used to, but for the price, it's ace.