Websphere app server or others

I tried this under "ask a question" and received no response, so I thought I'd try here...

Can anyone either tell me or point me in a direction to find out why we should be using "Websphere Application Server" (on AIX, if that matters), other than to put some money in IBM's pocket? What's the benefit of its features? What's the competition? In a (very) small shop environment that is writing the software that our < 100 employees business uses, is this worth spending money and time on? It is being heavily promoted to us and I would like to hear some non-IBM (sales) opinions.

Thanks for any suggestions or direction you care to offer.