Rick, sorry for the delay.
In my humble opinion, the 120 doesn't compare to the 107,
and vice versa. The blade stock on the 120 comes-in just under 3/16ths of an inch. The 107 is true to its 1/4-inch specs. The 120 has Buck's quintessential hollow grind, while the 107 has a deep saber grind.
Both feel blocky in the hand: the 120 because of crazy-thick scales and a damn-near complete lack of
any kinda' handle contouring, and the 107 because of a bit of a wonky handle design. In terms of weight, the 107 feels heftier in the hand, but not by as much as someone might presume. I think both knives will easily handle just about any reasonable "camp" task you throw at 'em. The Buck will come out on top with some, while the 107 will dominate others.
As far as what you're "missing"? I really can't answer that. I actually hate recommending
anything to anyone: restaurants, vehicles, guns, knives, etc. We're all so very different that it would be inevitable that many folks would not like something that I truly love. It's interesting, however, that you mentioned the TBT-1. There were many factors (*another story for another time) that led to me acquiring my first 107, but one of them was that I wanted the reliability and durability of my TBT-1, just in a more "conventional" design.
I know that I'm longwinded, but wanted to mention a couple other things...
-I wear medium sized gloves, and my fingers are
absolutely built in my image: short, fat, and pear-shaped. Over the years, I've been able to adapt to the handle on the 107 and actually
quite like it, now. However, no matter how much I use it, I just can't seem to get used to the handle on the 120. I keep thinking that I may have one of the Makers here give it a little contouring, and probably
will at some point.
-Whatever the grind angle is on the 107, it has some kind of "black magic"/"Jedi Knight" mojo when it comes to batoning. I own a sh!+load of knives and have
never found another that batons like the Steel Eagles. Like 'em or hate 'em, many of the YouTube knife guys have felt
compelled to mention the same thing, from Aaron at "Gideon's Tactical", to the "DBK" guys, to Christian at "Preparedmind101". I think C.J. Buck tried to harness some of that magic with the 108 "Compadre" Froe. And, while he got
really close, he still didn't hit the mark.
-I've spent years purchasing blades that looked very similar "on paper" to the 107. (*physical specs) Every. Single. One. of them has handled and performed differently, not only in comparison to the 107 but also in comparison to one-another. For me, I guess the Steel Eagles just have some kinda' spell over me.
Anyhow, my apologies for the long post. Happy hunting.
The 120 "Frontiersman" and 107E "Steel Eagle"...
All similar, all different...