wrote ...

But they are also hard to control at slow speeds, and imo use a
lot of gas.

That depends on the pump design. The Hamilton 212 has large reverse buckets
that provide excellent low speed control. I can rotate my boat in its own
length. Fuel efficiency is also close to a prop.

Another thing which I haven't had to deal with is that
they can suck a rope up into the jet, and then you have hell
getting it out.

That's true, it's good to avoid that although some provide an access hatch from
the top.

-rick-