i’ve used an iMac 24 for almost 2 years now. My MBPro 15 was nothing but trouble - i think it was a 2nd Gen release - i never buy the first

but i’ve got a couple of white macbooks that are rock solid, except for the brittle cases.. It’s a good combination. The iMac 24 is probably the best desktop I have ever worked on and unless you’re a hardcore video editor, running maya or some other crazy-intensive software.. the iMac makes sense over the Mac Pro which is just too costly.
My biggest consideration, besides getting old and needing the sharp screen.. is if you’re a MODx person then you’re probably prone to working in text editors and the large screen is a big help when you have a lot of text editing going on. it’s not uncommon to have photoshop, coda, terminal, documents and several other things all running at once in the middle of a web project and the 24" screen really helps make that work.