I've never actually used the LaRue, but based on what I've seen/read, the only advantage the Troy has over the LT for peeps without a 203 is the ease of installation. The Troy is def well made and sturdy, but it's a little large and heavy for my tastes. The LT looks much lighter and slimmer, while the Troy feels like "holding an elephant dick" as my roomate comments every time he holds a large RAS...this phenomenom is exacerbated by thick panels such as the TD/LMT type. It just feels huge.
Also, the Troy is not as continuous as one might be led to believe from photos and descriptions. On my buddy's factory assembled LMT M4 upper, the Troy is a little bit lower than the receiver. Maybe it's the upper, I don't know. Just stating what I've observed.
I'd go w/ Grant, unless money is a factor, because the Troy prices are pretty damn good, and despite the shortcomings I listed, they are a damn good RAS. They are excellent in quality and function, just not my personal favorite.