I would think you guys should consider TC Server, its a variant of Tomcat from Vmware. Might be good in an enterprise environment, since most of them should be able to work it out, as part of there virtualization deals.
http://www.vmware.com/products/vfabric-tcserver/
PS - I have used WLS extensively. For some applications it might be good. For some you really do not need it. So its very much driven by use case, scale etc.
