I had no adverse handling issues with my BOB. For out of seat climbing, the trailer likes to resist the bike's side-to-side motion. Once I realized what was going on, this was a non-issue. I must say it felt kind of weird and squirrely to go back to a bike with no trailer. I see no need for a two-wheeled trailer since the BOB is rated for 70 lbs. I only haul about 40-50.
I never felt like the BOB was overtaking me on fast downhills. Oh, and a bike's forward inertia wouldn't be any different with panniers vs a properly loaded trailer, all else being equal. If you disagree, please explain. Think of a trailer like a canoe when loading. That is, the heaviest/densest items in the centermost point of control. With the BOB that's bottom center forward. I use a couple dry bags in addition to the large BOB dry bag with a couple bungees.
The pic is looking back on my BOB and my friend Pete who uses traditional panniers...NW Wisconsin in June
