Yamaha or seadoo ?

I'm buy my first pwc. I know I want a 3 seater. I'm looking at a 2003 Yamaha FX140 cruiser with 39 hours and a 2003 Sea-Doo GTX 4-TEC with a 140 hours on it. Which should I get? Both come with trailer tow rope and tube. How do you relate hours to miles? Is there a certain hour that means you need a overhaul? What are the most hours that can be put on a pwc?