I have a 14' foot round trampoline and it works great.
The thing about rectangle tramps is that yeah, they bounce higher (most of the time), but you can only trick facing one way. This doesn't really matter that much at all actually lol. But yeah. Mine works great, they just need to be worked in a little, and they bounce super well when wetted a bit. Depending on what budget you have, here are some good options.
my friend has the circular one of these and it bounces super well. And you don't bang your shins up on any stupid metal sidebars (happened to me and I had a small fracture on my shin). so ya that's a huuuge plus. so ya if you have a Costco membership those are good.
And here's another one if you have a bit of a bigger budget: