I've got a 250EX and haven't had a whole lot of issues with it. I bought it new 1 1/2 years ago and still believe that it's hard to get a pilot house design for the price range Defiance offer's.
I wish it had the beam that a Parker has but I never shelled out the type of cash Parker gets for their boats.
The few problems I've had was the center hatch leaks and didn't have any caulking when installed from the factory. Trying to fill my fuel tank (which is plastic) for the 2nd time ever resulted in the fuel overflowing out the top and was unable to put fuel in unless is was at a trickle pace. I had a mechanic come down to my slip and soon found the problem was the vent hose was too long and was lying on the hull below the tank level.
When I filled the tank for the first time, some gas naturally flowed into the vent tube as well and created like a "vapor lock" condition. To correct it, the mechanic merely cut the hose shorter and ran it in a more direct straight line to the hull fitting.
You need to keep treating the sliding side windows with bleach every now and then because a green moss develops in the felt seal and makes it a pain to open. It's not Defiance's problem but it happens from being wet alot.
One interesting thing to note is: I've been hearing the same complaint about cracks in the swim step where the motors bolt on. There's a propeller shop in Oxnard, Calif. that's done repairs on a couple boats so far! I've been keeping an eye on mine after each trip.
One thing I do hope is that the Defiance folks come out with some "kits" or modification type options that could be purchased to improve storage in the Defiance. I've got batteries filling one space under the seat, squid lights and cords in another. Space is very limited to place registration paperwork, manuals, charts etc. , gooey stuff like sun screen lotion, snacks and misc. smaller items.
Bottom line I'm still happy with my purchase, even though I am a bit concerned on the swim step. Just keep a close eye on it.