The key to "long term" has nothing to do with who put the trailer together. It's all about how it is used and maintained.
We don't have the smoothest roads and bouncing down them at 60+ MPH, things (screws, nuts and bolts, plumbing fittings, etc) are going to come apart. Rougher the roads, the more things will come apart.
Proper maintenance of wheel bearings will make them last longer.
If you store it outside, you'll need to be more proactive with inspecting and fixing cracked caulking.
If it is regularly parked in dirt or grass, versus gravel or pavement, your tire will not last as long.
You need to be concerned with matching up the truck and trailer, weight wise, and a floor plan that works for you, much more than a name on the side of the trailer.
If you're going to use it in cooler weather, I would recommend a unit with electric heat pads on the holding tanks and sewer lines. Last time I was shopping, I was told, by a Keystone dealer, that Keystone does not, and will not install them. I'm currently on my second Flagstaff (Forest River product) that has them as a factory option. Some dealers order that option on all of their stock.