The 150 is marginally transportable. If you plan ahead, and can get your vehicle close to where you can place the binocular in its protective case, it is not too bad. The 150 is much easier to carry alone out of the case than in it. The case is very large and awkward to handle. It has small wheels under one end, but these do not do well on anything but smooth surfaces.
I can lift the case with binocular inside into a vehicle, but it's a grunt. Even more difficult is mounting it in the APM fork mount. One must be very careful to not get the tubes of the binocular against the side of the fork and ding them. Also injury and dropping it are always concerns.
If you plan on moving it around in a vehicle a lot I would recommend the 120. If you have a suitable vehicle, (pickup truck, van, or something with a large door and flat floor), and can develop a good system for loading and mounting it, the 150 can be workable. I have transported mine in my pickup, but usually take my Lunt 100 instead. It is MUCH easier.
My 150 is more or less permanently mounted on a home-made dolly with large wheels allowing it to be rolled in and out of the shop where it resides to about any location in the yard at home.