I'm impartial as I work for Frog so I'd rather not recommend. I just wanted to make the point that we have a lot of people join us because even though Moodle is free, they don't get the engagement they want from their learning platform because it’s too difficult for non techie teachers to use and create things in, which results in it costing them a fortune.
Like I said, have a look around, you've got lots to choose from, but make sure you get something that works to achieve your whole schools objectives and something that everybody will buy into – teachers, SLT, students, governors and parents – only then will you guarantee success.