Thomann ocean drums are fab! I have them in sizes 14", 18" & 22".
As you go up in size the sounds gets more realistic with move play, but on the down side they can become harder to pickup and hold. I've used and taken all of them out, individually, and all have performed superbly.
When choosing draw out a size template to get a feel for how the size will fit in your hands. 18" is the most popular of the 3 sizes of Thomann ocean drums that I have with my students.