We owned with Moorings for about 6 years. The majority of our trips, we upgraded to other boats, so we used a large variety of boats. From brand new to exiting the fleet any minute..

New or old, we had a problem here or there on many trips. Only one trip was it something that couldn't be fixed and that was on their 58' Cat (A/C), only about a year old at the time. Every other time, the problem was solved very quickly. And with hte 58, we were offered a 48, although with just 2 nights left we decided not to bother.

Issues on other trips ranged from a broken shower spray on the transom, to the generator not working, to an engine over heat issue and a number of other minor items. Most common was the A/C not working and needing to be bled, but after having this happen once or twice, I quickly learned how to resolve it.

End of the day, all the issues we're resolve quickly and none really had a significant impact on our trip.

So while I would highly recommend the 3900 or 4000 as the owners versions are awesome (non-owners as well), I wouldn't be concerned with spending less on an older boat. At least not with Moorings. I can't speak to the others having not used them.