Both are USA based hosting companies, Bluehost based out of Utah, and HostGator based out of Houston.

Statistics

Hostgator hosts more than 2,500,000 domains and 200,000+ active customers, Bluehost with Hostmonster and Fastdomain host more than 1.9 milion domains and have more than 500,000+ customers. Number of employees for Host Gator: 260, Blue Host and others: 240+. So here they are pretty much the same in statistics.

Support

Both Host Gator and Blue host offer support via live chat, phone and and e-mail(tickets) 24 hours a day, 7 days a week.

Features

Almost all hosting features (PHP, MySQL, cPanel etc etc) are shared (same) between these two hosts.

Hosting Services

Blue host offers only one shared hosting plan, while Hostgator offers three shared hosting plans, reseller, vps and dedicated server hosting. This is where host gator beats Bluehost. With Hostgator there is room to grow if your sites become very popular, while with Bluehost you have only one hosting plan.

Reviews and Rating

They have received good reviews from users and hosting reviews sites. Both have good rating and are listed in top 10 best web hosting providers.