After becoming so wistful to get the arena gloves that give cat druids a true spell interrupt, I looked and found I had most of the points in the bank so I bought a pair. I really, really like them for PvE.
The effect is quite powerful: they turn Maim into a true spell interrupt complete with casting lock-out. In Black Temple I was able to interrupt all sorts of spells being cast by trash mobs that are immune to the incapacitate effect of Maim. I was able to interrupt Blood mages' Bloodbolt, Deathshaper's Shadow Bolt, Heartseeker's Rapid Shot, etc. Unfortunately I wasn't able to test it on any bosses, but will try to soon.
There's some sort of logging bug; both my scrolling combat text and my WoWCombatLog.txt keep telling me the mobs were immune to Deadly Interrupt Effect and my logs show no successful interrupt except once, against an Aqueous Spawn's Sludge Nova. I have a theory for that: the other spells I was interrupting are in the Physical school and presumably you aren't allowed to lock out Physical. So maybe the "immune" is showing immunity to the lockout while the actual interrupt still worked. Fine by me, I'm not that interested in the 3 second lockout. I'm confident I was stopping the actual spell cast. (To research: looks like our gloves share code with the rogue Deadly Throw interrupt, do they have the same bug?)
The gloves are pretty easy to use. The stats are good even for T6 geared druids. I'm using them full time in my trash tanking set now; the resilience helps with crit immunity and I can play with interrupts after my tank target is dead. It does take a bit of adjustment to have Maim available while DPSing. I found it worked best for me to try to maintain 35+ energy at all times (as opposed to going to zero) and to only re-apply Rip when my last Rip was finished ticking, to keep the combat points in reserve. No question that using Maim will lower your DPS, but it's fun to try. And on certain boss fights spell interrupts are essential. With these gloves I have significant new utility in cat form.
With Wrath around the corner it's getting late to be gearing up but I encourage feral druids to look at getting these gloves. The S3 gloves cost 900 arena points, about 4 weeks. If you're patient the S4 gloves are noticeably better for 1125 points; no rating required. I really hope Blizzard considers putting an interrupt effect like this into WotLK gear. It gives feral druids some very interesting new tricks.