I am also pretty impressed with namecheap.
I found their support very responsive, especially for that price. Just yesterday they have set up my personal nameservers within 12 hours. And they let me pay by paypal as well (which not many registrars do).
Of course there are glitches in the system (I experienced them as well), but they are usually solved very quickly.
They are not perfect, but for that price, they are certainly a great deal.
BTW: Has anyone ever had experiences with the directi reseller program? Their price is unbeatable and their upcoming API should also be pretty good as I heard.