I can honestly tell you that I rarely notice my BOB when I tow it. It's not as though I am in my mid 20's either or in the best shape of my life. The BOB isn't very heavy, about 13 lbs and is 4130 Chromoly so it is durable. Until it is very loaded the only way I know it is there is to see the little flag in my rearview mirror.

The way I looked at the 1 vs. 2 wheel design was based on whether I would be riding the bike or parking it the most. I have a different 2 wheel design trailer and while it is more stable parked I like it a lot less while towing it. Of course this is not the case if I have a large load that I can't balance easily on the single wheel trailer. Normally that isn't the case though. I'll have groceries or something else in it that isn't long and unwieldy. If I were halling lumber I'd go for the 2 wheel trailer for sure. If you are touring with it I'll stick with the single. I am working on a "kickstand" for my trailer that will flip up when I ride off so I don't have to worry about it being unstable while parked. It is quite easy to unhitch if it is a real issue.

FYI- the TW Bent trailers don't seem to have any connectors for hubs and I don't know if you could use them with the BOB ones. They look somewhat similar. I contacted the company in Taiwan and they said they had them but when I contacted the distributor here they acted like they had no clue what I was talking about even though I provided them with my original emails from the manuf.