The 399TH was a strong candidate, making the top 2or 3. But on the 399, there were a couple of things that we weren't keen on:
One issue was internal accessibility with the slides in. We wanted to be able to get to our fridge, bathroom and bedroom at rest stops or the occasional location where we can't put out slides. On the 399 only the one rear bath is accessible and only if it's not blocked by something in the garage.
Another issue was the washer / dryer prep. We knew we wanted stackable units versus combo, and we wanted the dryer vented to the outside. In the 399TH, the W/D prep is in the middle of the garage making venting difficult. There are also controls on the wall above the prep, meaning they'd need to be relocated, or some sort of cabinet build around the washer/dryer. All doable but a lot of extra work. Plus we really like the W/D in the bedroom.
The third issue was the patio on the passenger side and all of the nice big windows being on the driver side, which has a lovely view of the front of our neighbors or, better yet, the back of their rig and poop hose. ? We also weren't sure how much we'd like the patio since it really only holds 2 people. If you want to watch a game or something outside and have more than that, some will be on the ground looking up over the rail. In reality this never happens as it's usually just two of us. But it was something we thought about.
Everyone has different priorities and there's no such thing as the “perfect” RV, just perfect enough for you. If we could have everything, our RV would be 75 feet long!