> ...and I hope that the project has gotten much better over the years.

It has! They have made some significant improvements. There recently was a huge effort to separate the RC core code -- all of the stuff that talks to imap -- from the rest of the interface, so now people can easily build RC clones.

Also, relatively recently, they reworked their skinning system and got a new design professionally made ("Larry", now the default). You can get Roundcube skins for people who like Outlook, or want better mobile support, etc.

And if you've got managesieve installed, you can make your email do tricks that Gmail can't.