I do not really understand the lot of excitements for stable releases, because stable ROM is just an accumulated release of previous developer releases without root option, and without weekly updates. So, imo it is one step back, but up to you guys...
My 5 cents are given below...
Sorry for noob question!
Whats different for stable to dev rom?
Google apps, root, apps, transparent status bar, icons...... Etc
Every new function, every new feature that comes up to the phone is first thrown to the development versions. The features might be buggy, or might introduce other issues (regression bugs), or might be dropped.
Fixes for various problems are tested. Some "fixes" actually break things. Like losing suddenly your google account. Development versions are the testing ground for the MIUI firmware.
The stable versions contain all those fixes and features that have been mature: they do not present any problems (well, most of the cases). Plus, to improve stability, stable versions come without root capabilities, whereas development versions come pre-rooted.
So, if you want to fiddle with your phone and consider yourself a cutting edge user, use a development version. You might have to spend some time troubleshooting though, be prepared for that.
I
always prefer stable versions. There are very rare cases whereas I would go for a development version.