I won't waste much time comparing Registrars. Every Domain Registrar starts with www.icann.org. This is the company that controls the domain names and everyone re-sells their product.
Every re-seller connect to icann.org for domain name searches. Once you pick your domain, every re-seller registers that domain with www.icann.org.
Since all domain registration is virtually the same, why is there such a large gap in pricing between Registrars?
For example, HostGator is $12.99 for the discounted 1st year, Godaddy is $11.99 for the discounted 1st year, register.com is $5.00 for the discounted 1st year, and kvchosting.com gives you a free domain when you buy hosting.
In all these cases the price jumps way up after the initial year.
That's why we use Porkbin.com. The .com domain is $8.84 forever. They are the cheapest domain registrar I have ever found.
You can transfer your domain to Porkbun.com for free (unlike GoDaddy and Hostgator) and, at the time of this writing, they will add 1 year to the expiration date making it $8.84 for two years.
Do yourself a favor. Before the 1st year registration expires, transfer it to Porkbun.com and save some money.
Porkbun.com also carries all the domain suffixes. From .ac to .zone they offer it. Most other Registrars only carry select suffixes link .com, .info, .net etc.