I do use it on a few AP's... just be nice if I could use it on more... and not feel bad about it for being clearly inferior to the Blade. :P

Sometimes I want to take mana potions on Jarvan. I'm resisting the urge to get P. Ring there though

Usually it's hard for me to justify getting a ring when I can just rush guise and get better health and AP stats while still getting boots (obviously I'm talking about a boots + ruby + amp start, since you can't afford the guise). The mana regen only really seems important if you're playing an AP bot (Diana, for example) so I think it would be a good buy on her. Plus you have enough money to pick up a few bots with the ruby + amp start so if you need that extra mana to go top you can still get it.

Personally I don't think it's nearly as good as prospector's blade as lifesteal for AD is way better on CS than mana regen for AP.

Meh, I'm a top lane AP player, and Vesh I can tell you that the MP5 makes a difference for mages like Cass, Brand, Zyra, or Swain (well, saying Swain is kind of cheating, but still...)

If you aren't running MP5 runes or masteries, Prospectors Ring is always a solid choice on mana-using AP's.

Plus, its a goddamn gem-encrusted ring!
Gotta get my bling on, ya know?

Vesh, you remember life-steal is reduced 20%, and until you get some more AD that LS does next to nothing? :-/

P. Blade is better, but more because how important auto attacks are early game.

Well, I'd say it depends a lot on which champion you're playing with. For most of the AP casters, I rather get a Tome + pots...however, I find it to be really effective to begin with prospector's ring + boots + pots when playing as Diana...but hey, opinions are like butts, everybody has one.

Going to be testing out 30 AP/6% SV in conjunction with a modified global mana aura.

I think the problem here is the item seems weaker in comparison to the others, Most AP items like both scepters, RoA and rabbadon's are actually quite expensive and have no particular helpful component in the period you are saving, for them excepting for RoA that has the catalyst and Archangel's that has the Tear which is a so so item unless used in Kass, Ryze, Zilean or Karthus, sure +430 hp from gian'ts belt seems really cool but it's already been proved that Hp without resistances is pointless and that a giant's belt start severely handicaps your damage potential exceptng if you are Darius so most people feel better with jsut a blasting wand start, than starting with the Ring and having to get the Big( and only) ap items from scratch. i myslf always get the Ring because as i already stated on Dominion you need the most bang for your buck as soon as possible and a single stat alone is a real waste on a map that's completely focused on combat,the Ring gives me that although sacrificing a bit of late game power, then even though you sacrifice late game power running around with a pros Ring makes me feel more useful than running around with a giant's belt being literally a 2500 Hp Punching bag.