There are some key differences between Nomorobo and the Ultimate Call Blocker.

1) Ultimate Call Blocker features a Global Blacklist service managed by HQTelecom and works with all providers (VoIP & Landline). It only requires Caller ID to work.  HQTelecom's Global Blacklist service currently has over 200,000 unsolicited phone numbers.

Nomorobo only works with some VoIP providers but not landline service providers such as AT&T, Verizon Standard, etc.

2) In addition to caller id, Nomorobo also requires a special service called "Simultaneous ring" service -- this usually requires additional monthly cost.

Ultimate Call Blocker does not require any special service in addition to caller id.

3) Ultimate Call Blocker / Global Blacklist service includes scammers, and ALL unsolicited callers.  

The Nomorobo service focuses mostly on robocalls.

4) With the Ultimate Call Blocker , you can manage your phone lists online, including Blacklist, Whitelist, etc. 

Nomorobo does not offer any list management capability.

5) Whitelist Mode is a service mode that allows users to block all incoming calls except from those numbers in the user's whitelist.

Nomorobo does not offer any Whitelist services.

6) Name Blocking is a feature only available in the Ultimate Call Blocker.  This feature allows users to block incoming calls using names, in addition to phone numbers.  

Nomorobo does not offer name blocking.