As a regional caster, I find it a lot of fun, as usually it is related to the event in one way or another. Unfortunately, the spells are sometimes not balanced, and this is usually because, when not they are not set to one area (aka, Chimeron or Folkestone regionals) they are made specifically for that quest, and every spell is going to be useful at some point. As a small point i'd like to mention here, protection from undead is only second circle because undead are rare. Pro-enchanted is sixth circle. Protection from [CREATURE WE ARE FIGHTING] should be closer to sixth than second.
Whenever I've played a spell caster I tend to keep a few regionals in my build for a few reasons. Mainly it is because having some new tools to play with at each event tend to be fun, however I have also found that regional spells are generally wildly unbalanced, usually in favor of those who have the regionals.I think Mikey makes a good point in that EHs may not fully take the spell into context in the scope of the event they are throwing.Regionals are a good way to playtest new mechanics, or a good spot for spells that might be more geared to Tournaments or Questing. As an EH I like to make sure that the regionals my event holding crew and I use are public, because I find that the players will often times enjoy themselves more when they know what sort of mechanics they will be interacting with, although mystery is nice once in awhile as well.
I went to an event of a game vased on Realns once. There was a "regional" there called Elvin Fire Circle. To understand why this spell was annoying think of the game's Circle of Fire which operated much like a CoP. However, the Elvin Fire Circle was not public knowledge nor was it exlained when used. Turns out it was little more the DnD's fairy fire. Those if us who had been "trapped" in the spell were pissed when we later learned we could have just walked out.Although my examplyle is not Realms, I think it still applies. Regionals should be public.