If you are not going to take advantage of the ATX/STX modularity, excluding the BTX, then it does not make a lot of sense to buy it. You are paying quite a bit more money and taking weight penalty compared to the ATS/STS with only a bit better glass. There are other options, such as Kowa models with fluorite lenses, that may make more sense.
Here are the specs for my STX with the 65mm and 95mm objectives:
* 65 (with Swarovski stay-on case)
** Length: 15"
** Height: 5.5"
** Weight: 66.15 ounces
* 95 (with Swarovski stay-on case)
** Length: 19"
** Height: 6"
** Weight: 88.25 ounces
I love the view the STX 95 provides but it is a beast. Plus I have to take a heavier tripod/head (74 ounces) to provide the necessary stability. The STX 95 goes with me when I am helping someone else on their hunt, scouting, and the occasional Coues hunt; most Coues hunts I just bring the STX 65. My STX 95 "setup" with tripod and head weights just over 10 pounds. That is 20% of the usual 50 pound max weight limit for a lot of flights to the backcountry.
The STX 65 gets the nod the majority of the time due to its size and weight. Works pretty damn good and I can use a lighter tripod/head (54 ounces). There are times I wish I had "more"; but I've ran the STX 95 and have had times I wished for "more". My STX 65 "setup" with tripod and head weights 6.75 pounds. That's 13.5% of the usual 50 pound max weight limit for a lot of flights to the backcountry. This is one reason I grabbed my Kowa 554; entire setup only weighs 4.75 pounds.
Note: I know that I can save some weight on the tripod and heads but those are some expensive ounces. Included what I have for demonstration.