The eesha salaah timing in the masjid in my neighborhood is usually very late. In fact during winters (like currently) they delay the salaah to the extent that sometimes it is nearly 35 minutes later than the neighboring masajid. So much so that I prefer going to the other masjid and completing my eesha salaah there.
I am not aware why they delay eesha salaah to such an extent that it becomes inconvenient for everyone (or maybe just some), however I think this may have something to do with hadith of the Messenger (SAWS) that the eesha salaah would be the last thing he would do before retiring.
I have a feeling that we may quite possible have misunderstood the import of this hadith: he would not intentionally delay his salaah; rather it was the last thing he did before retiring, regardless of the time. There is a difference between the two statements: it is not automatically implied that the Messenger (SAWS) would delay his salaah. This is especially telling since he (SAWS) always insisted on praying as early as possible, and I don't think eesha salaah should be excluded from this injunction.
I would be grateful if anyone with knowledge in this area could throw some more light on this. My knowledge in this matter is sketchy at best.