Aside from what Boykin mentioned, a significant advantage of using an IP phone like this, vs. using an ATA like the 1xx or 2xx series, is the audio quality.
When you use an ATA, with a conventional analog phone plugged into it, you add several more rounds of digital<-->analog audio conversions. Each time this happens, sound quality is degraded somewhat. Example: Mary calls you on your phone number, which is provisioned on a OBi 200. You have a cordless phone plugged in to the OBi.
Mary's cordless telephone digitizes her voice and sends to her base station, which turns it back into analog, which goes out over her copper phone line-->central office, digitizes it-->over the various phone carrier networks-->your SIP ITSP-->your OBi, which converts it back to analog to your cordless phone, which digitizes it again, and then turns it back into analog on the handset.
If you use the IP phone, you omit the final digital-->analog-->digital-->analog conversions. Additionally, the 1032 has (in my opinion) really high-quality audio circuitry, designed to support wideband (HD) audio. Even if the call is over narrowband telco, the resulting sound quality in the earpiece or speakerphone is outstanding.
Aside from all that, I really like my 1032's feature set. The firmware is still a little rough, but it's getting better. Mark from Obihai just posted a really great tutorial on how to set it up.
