Xpressions does Auto Attendant as well as many other useful features. In addition to auto attendant, you can build menu trees, which are essentially the same thing. You get an "Application Builder" to build them on, which is a nice GUI interface. Unify has a good class on it too.
Dial by name and voicemail to e-mail (as a WAV file) is included too. You can also install a PC application to get your voicemail or direct users to a web page to access their mailbox. Xpressions does other things that are licensed, such as FAX, SMS, Exchange/SAP/CRM/UC integration, and I'm sure a few other things.
Licensing is based on features desired, user licenses, channel licenses, and languages. For a basic setup, you'd need to identify how many users you want to support (number of mailboxes) and how many voice channels you want active at a time (think how many people would access their voicemail at the same time).
Would I recommend it? Definitely.
LoPath
Maintain HiPath 4000 V5 & V6, OpenScape Xpert V4, OpenScape Xpressions, OpenScape Contact Center V8, OpenScape Voice V9