Scott,
Glad to hear the factory unit is so reasonably priced. Kinda makes the decision pretty easy don't it? I'm glad Chuck brought up the point about the seatbelt, I forgot to mention that. I've seen tractors have seatbelts without ROPS. All that does is make sure you stay with the tractor so it can crush you when it rolls.
Charlie,
I agree with you in the fact that the factory isn't the only one who can build a ROPS, BUT they happen to have some extra tractors to do rollover/crash testing to make sure the structure will hold up in a variety of situations. I'm a very experienced metal fabricator and a certified welder but I myself wouldn't build a ROPS for a machine that I know has a factory unit available. I'm not willing to risk someones safety for something I might have overlooked or done wrong, I'm willing to bet any trustworthy fabricator/welder would feel the same.
Comparing a homebuilt ROPS with a homebuilt boat is not an apples to apples comparison. The boat is a piece of equipment much as the tractor is. The PFD you wear while in the boat is a piece of your safety equipment kind of like the ROPS and seat belt on the tractor. You wouldn't think about trusting your life to a PFD that was made by the seamstress down the street, "It looks almost like the factory built ones", would you? What type of foam did she use for floatation, has it been tested to prove it works? As far as building your own boat, do most builders finish their boat and go duck hunting the next day? From what I've seen most guys take 'em out and test them in warmer weather so they can make any adjustments needed before the season starts.
I'm not trying to start a fight or arguement but when it comes to safety issues like this I feel very strongly about doing things right. I've seen first hand what happens when things go wrong involving tractors, big trucks and heavy equipment. I've seen people wind up dead or missing pieces of their bodies, it ain't a fun thing to see! If I can climb on a soapbox and maybe prevent an accident I'll do it.
Thanks for listening (as I step down off my box (insert smiley face here)) and have a fine evening!
Jim S