I've done so many transfers in the tub that I had to buy kneepads (our floor is tile and after a few hundred transfers anyone would hurt!).
the "slide and place" method that's already been described is a great idea as well as my idea which consists of taking a risk and opening the container inside the new enclosure and letting the spider naturally come out into it's new habitat.
i just unpacked a MM OBT last week. Definitely the trikiest T i've had to rehouse yet. i also do all of my rehousing and unpacking in the tub as well unless i'm working with a large, slow, docile species and i am already familiar with that individual T. Anyway, i prefer the tub because it gives me a large, open area to work; where i could hopefully catch a runaway T easily if needed. My bathroom is also always very clean and neat and there aren't nearly as many places for a T to hide if it escaped. However, i was always under the impression that some T's can climb the tile wall above my bath if it tried, though never had that happen - not even with my Pokie. Well, i can tell you that this OBT had absolutely zero problems running up my tile wall in true OBT fashion.A bit of both actually... Depending on the bathtub, some inverts have trouble climbing the side of the tub, and trust me, it's much easier to have them confined to the smaller space of the tub than the bathroom itself