As no one else has replied yet....
I only had it briefly and then respeced it out. Needs a bit of slotting to make it useful and I just never found a use for it myself. 8 second stun I seem to remember which wasn't enough time to do much and I could have already launched bother Nova AoE in that time. I know a lot of people love it though.
If you have a plan that involves stunning a group and can spare a few slots (couple of acc, end red and stun duration probably) then go for it. 
I'm thinking it might be useful to stun them then switch to nova for a few aoes, then back to dwarf for when the stun runs out.
8 seconds unslotted isnt too good though. hmmmm.
Got me killed everytime I used it on my PB 
Only used it like 3 times before respecing it out though...
that the big thing of light?
i got it, it rocks really handy, good recharge time too if u slot it will with acc, rechrg, n disorentate.
My new PB isn't high enough yet to have tested this, but I was planning to include it in my build with 2 accs, 2 durations and 2 recharge reduction SOs.
According to Hero Builder you can get it more or less perma (very slight overlap) by slotting with with 2 durations and 2 recharges and firing it every 25-26 seconds.
...mind you the builder seems to say it has a 15 second base duration (rather than the 8 quoted above) and 45 secs recharge...
From the reading I've done on the US forums it seems the Mag is high enough to affect Minions and Lieuts, but won't affect bosses without criticaling. If it IS possible to get perma-effect, then you could basically take the minions and lieuts out of the fight while you beat on the bosses. Might be handy for Nemesis missions! 
...anyone actually tested the duration/recharge when slotted?
Replying to my own post, bad form i know... =D
I'm now level 35 on my PB, so for anyone wondering:
Pulsar can be made just short of Perma at about the 25 second mark Using 2xAcc, 2x Recred, 2x Hold duration.
With Hasten running, it's perma.
By itself it mezzles minions 100% of the time, lieuts a little better than 50% of the time. Does not Mez bosses.
Worth it? Heck yeah! Especially for a Human form blapper build... Pulsar + Solar Flare = Crowd control!
Only gripe I have is the quite long activation time.
If you use SS and Stealth beforehand though, it's not an issue...
thanks for the update - I'm getting it at 34
I think it lasts more than 8 seconds unslotted.
The biggest problem I see with it is that it misses a lot (with one acc SO). The animation time could be shorter too. But it's useful to get some time when the place gets really crowded.
I found it very useful on Saphire.
Specced it out for her ED build, then put it back in when I got to level 47, when I realised how much I missed it .
i am only 22 but i dont think i will get it cos i am respecting when i7 is out and getting fitness it should be more helpfull
Appears to be effective no matter what level the mobs you're fighting, have only noticed a very slight decrease in duration for higher level mobs. With 2 Acc/2Holddur/2Recharge in it, can reliably hit purples and keep them mezzled for a good amount of time (against purples with hasten up, I believe you can set it on autofire and it's just short of perma again).
I've just gotten started into carnie mission arcs and tend to fire pulsar off after the tank runs into a new mob, so far it's proving an effective countermeasure against their psi damage and endurance drainage. Can always Quantum flight or Essence Boost and switch to dwarf anyway if we pull too much aggro... Dwarfie's actually fairly good at taking care of Dark Ring Mistresses, especially with an End Buff
Another extremely good use of pulsar is right before you fire off a Thunderous Blast (indeed I usually Essence Boost >> Conserve Power >> Build Up >> Pulsar >> TB, then pop one blue and keep on fighting). If any Minions or Lieutenants are left standing, they will likely be mezzled and you won't get anywhere near the amount of retaliation coming your way.
I switch a lot between dwarf and human form and I am wondering if pulsar will be useful to take?
If you have any experience please let me know.