I trust Hexonet more than other registrars, due to the highly sophisticated backbone of their systems. I would rather pay $10.00 to Hexonet for .com than $6, $7, $8 to other registrars that utilize low-grade infrastructure and provide questionable interfaces with which to manage domains.
Hexonet are unique in that they position themselves as a "wholesale" domain registrar rather than a retail registrar, which means they're are a great choice if you run a web host or sell domains and hosting to clients as they have some features aimed towards those types of customers. These include a fully-featured API (anything you can do through their site, you can also do through their API) and the ability to customise the WHOIS listing for your domains (to show your company name).
Having said that, they do not have any minimum purchase amounts like other wholesale registrars do, so they're still a good choice even for "regular" domain registrations. I've found that the prices for some TLDs with them are quite cheap compared to other registrars, and they do offer a very wide range of TLDs.