Sure, I got to use both, as late as a month ago. I had a two wheeled trailer, with handling characteristics very different from the BOB. The roads featured all sorts of annoyances you may not encounter along the Pacific Coast. Things like rumble strips, cattle guards, and snow drifts (yes, it was that late in the season), convinced me to switch halfway through.
Trailers are heavier, and are simply too tempting to overpack. OTOH, they detach easily, have rock solid stability through turns and winds, and make a handy clothesline. I would recommend them when mixing lots of local riding with your cross-country touring, or when you cannot avoid packing a lot of equipment. Panniers would be for rougher or unknown road surfaces, and for lighter/faster touring.