elkaddict, what is your budget? This can get really expensive!
In general, you will pick up more detail with both eyes involved in the image just due to more information sent to your brain. You will also experience less eye strain over long viewing sessions with two oculars vs a monocular.
Pulsar's stuff is pretty good, and I have no doubt their Accolade series is good. I haven't tried their binos and handheld monoculars but I have used a couple Pulsar scopes and I own the Thermion scope (XP50 model 640 res) you referred to, and it has served me very well with outstanding image quality and a very nice feature set.
I would avoid anything FLIR now that they have stopped producing products for the non-military consumer market.
Another great bino option is the N-Vision Atlas. I have the 50mm version, and it's outstanding! It has 640 resolution with the superb BAE OASYS 12-micron core, 3.5X base optical mag, very simple, user friendly controls, very tough robust and waterproof construction, takes still pics and video, and has long battery life.
In the interest of accuracy, keep in mind that most thermal "binoculars" are in fact "bi-oculars," in that they have 2 ocular display screens but 1 objective lens system. This is an important distinction, because they are expensive enough already, and a true thermal binocular with 2 objectives is uber expensive.
Besides price, there is one other main disadvantage to a thermal bi-ocular/binocular vs a monocular. With both eyes looking at bright screens in the dark, both your eye pupils become dilated so you experience momentary night blindness after any extended viewing. You will then have to stay still and allow your eyes to readjust to darkness before moving again after use.
