My understanding is that version 3.0 will probably merge the Membase and Couchbase products into one, so you'll have Couchbase and Couchbase mobile.
BigCouch is a separate product from the Cloudant guys, which is essentially CouchDB with an elastic sharding layer. Cloudant also sells a hosted version of BigCouch with -- I think -- a Lucene engine on top. There will likely be some overlap here between BigCouch and version 3 of Couchbase Server.
IrisCouch is a hosted version of Couchbase, with GeoCouch thrown in as well.
"Then you have no officially maintained libraries for the different platforms which was a turn off to me the first time I cracked that egg open."
I think this comes out of the initial popularity of CouchDB-- a bunch of people wrote drivers for all kinds of languages. Some of those guys work for Couchbase now. The libraries at http://www.couchbase.org/code/couchbase-single aren't comprehensive, but they do give you a good idea as to what's out there.
There was a bit of digging involved to get a lot of driver and connection information, but it seems like the Couchbase guys are doing a great job at cleaning up what was previously a scattershot list on the Apache site.