The call quality, stats, logging and 'uptime' more than compensate. The UI is overall quite clunky compared to others - for example, the history view needs a little too much interpretation, there's no 'redial' and there's no simple hotkey for 'quick, dial me a number'. The multi-way calling is great, but hold is a little flaky. Compared to the competition, it scores about 98% uptime compared to about 80% for the next-best.
This is important to me since I have to rely on this for important incoming calls. Uptime for me is a combination of registration, stay-alives, non-dropped calls and other operations that keeps the phone ready to ring and keeps the call active. Generally, most softphones are great with outbound calls, but Blink Pro wins on incoming call 'uptime'.
I use this as my main 'desk phone' on my Mac after failed attempts with iSoftphone, Zoiper, Telephone and others.