A little late to the discussion but I just did a walk-through on both a Keystone Passport 3220BH and Bullet 308BHS, both of which are twin units. Both units were a 2016. The sales rep told me that the Passport has been around longer than the Bullet (only 4 years for the Bullet).
My impression was this. The Bullet was a step up in terms of amenities. The aluminum rims, extra pantry space, extra overhead sofa cabinets, and solid sliding interior doors (vs curtains) for the Bullet gave it the edge. It was also priced about $500-600 more.
The only thing that grabbed my attention on the Passport was that it came with a standard queen size mattress (60x80). The Bullet has the RV queen at 60x72. It's funny because there is definitely enough space in the front bedroom to accommodate the larger mattress. Just need to add longer support wood on the platform, one of the first things I will be modifying.
I must have walked between the two units at least 5 times. Everything else was cosmetic differences. Quality of wood trim, fabrics, and craftsmanship was just about the same.
If you're looking for a bunkhouse model that is light enough to tow with a 1/2 ton vehicle and won't dent the bank too much, take a gander at these two. That extra bunkhouse slide is was sealed the deal on this floor plan over the many 1 slide, quad bunk models on the market. You can fit 5 kids comfortably in the back, and even set up a full size pack-n-play in it.