Ok I am having a hard time deciding . I spoke with Chris the owner at ULA with issues on which ULA to get He suggested the catalyst since I am downsizing the problem is I have the 5000Cubic In Kelty Red cloud now and the Catalyst is 4600 CI so I am only dropping 400 CI compared to Circuit 4200 which I loose another 400 CU total 800. I want to drop pack size and weight lets start with major gear I will carry. Bag Montbell SS # 2 hugger 650 fill down 2lbs , Tent yes tent hate bugs Kelty Grand Mesa II 3 lbs my food is compact I bring dehydrated meals maybe 5 lbs have a texasport 3 qt pot and cat Can stove with wind screen and stand and fuel all 1.5 lbs a Hiker Pro filter a change of socks underwear and a pear of sweats a Rain/ wind jacket and maybe a fleece top. a 32 oz powerade bottle of water and MT 2 lt platapus water jug for camp. I will have weight below 40 lbs I am afraid I may buy the Catalyst then down the road it's really two big and should have bought the circuit I hate decisions like this . I think oh hell spend the extra 50 and you will have the extra room if needed for winter or extended restock trips. any suggestions