I've had a Lunar Solo E for many years, and my partner last year had a new Skyscape Trekker. Both are excellent shelters.
Differences I've noticed:
The LSe can be pitched at a variety of peak heights depending on the weather. Not so the Trekker.
The Trekker is better ventilated with mesh walls on two side vs. one for the LSe.
They have the same total vestibule area, but that is all in one vestibule for the LSe (great for a large pack, dog, or small child) while there are two separate and smaller vestiblues in the Trekker…..AND….
You can not access both vestibules from inside the Trekker (a design flaw IMHO) while the entire vestibule area in the LSe is immediately available and accessible.
The LSe requires only one pole to set up; the Trekker takes two.
The Skyscape is available in three different materials, including a rediculously light cuben version (the X), each with corresponding weights. The LSe is only available in silnylon.
Closed up completely, the LSe is less prone to condensation than is the Trekker, which turns into a condensation station without a good breeze. With both vestibules open, condensation is a non-issue with the Trekker.
If I had to pick one, I'd take the LSe, but remember, mine is the older version with more floor space (but less headroom) than the current LSe model. If it were not for the $450 price tag, I'd sure like to try the Skyscape X.
The Trekker beats the Rainbow everywhere but cost; it's $10 more. That said, I also have a Double Rainbow. Were I to choose between the RB and the DRB for a solo trek, I'd take the DR every time. Yes, it's 7 oz. heavier, but you get 7 more square feet of floor area and more importantly, TWO vestibules and TWO doors, tremendous cross ventilation (better than the Trekker) and you can really sleep TWO adults inside comfortably with room to spare, although your packs will live in the vestibules or under your legs. It's a palace for solos.