One group hails from England while the other hails from America. They're both working on dominating the world's music scene and it's safe to say that they're both on their way.
The groups are successful and talented in their own right and I think their fans can be thanked for the success of each group. Because without the fans support they couldn't have been as successful as they are.
Both LM and 5H have had their albums debut in the top 15 of the Billboard 200 Charts as well as both having platinum singles. Sure, Little Mix is at a bit of an advantage given that fact they've released 3 albums and are now working on their 4th. But Fifth Harmony have an advantage too. Their advantage is that they're American so therefore it's easier for them to crack America. A thing Little Mix is working to achieve
Fifth Harmony's debut album Reflection, debuted at no. 5 on Billboard 200 Charts. 5H's sophomore album 7/27 will be released in just a few days time on the 27th of May.
Little Mix's experimental debut album DNA, debuted at no. 4 on the Billboard 200 Charts which broke a record that was previously held by the iconic Spice Girls.
R&B-inspired sophomore album Salute, debuted at no. 6 on the Billboard 200 charts. The 80's-pop sounding third album Get Weird, debuted at no. 13 in the US.
As you can see both groups have had incredible sales with albums so far in their careers, and I won't even start to talk about Singles because they've been just as, if not more successful.