Does it ever jump out of first when you accelerate?

Nope, never had that problem.

The clutch feel sounds like the hydraulic system has either air or water in it.

Sounds reasonable. We'll take it back and get them to bleed the line, etc. I'll also check on what we actually spent on the previous parts & labor on the repair.

Other seems to fix that problem by changing their clutch, but opinions seems to be contradictory on this point...

Changing out the clutch or transmission would, presumably, be a much more expensive repair. I'll try the throttle blipping and other tricks to see how well they work.