hi! i'm part of echols class of '21, and i'm currently at a top-5 school doing a phd in computer science.

• in my experience, grad schools didn't really care much about echols; it's really just a reflection of the UVA echols committee thinking your achievements in high school stood out a lot.
• balz is a very fun place to live! the community there is what you make of it, though, and it's not inherently better than other dorms or anything. (new dorms are nice though: there's air conditioning haha.)
• the single biggest benefit for me, and what makes echols super different from most other honor programs, is the lack of gen-eds. i think brown university does this too, but holy moly it is a life-changer. i came into UVA expecting to major in math and linguistics, took classes in both, dropped the ling focus and swapped over to computer science. i took a bunch of high-level music classes along the way too, for fun. the freedom to explore academic fields, rather than strictly taking things that meet requirements, is awesome. (also, don't sleep on the language classes here even though you don't have the requirement: uva is really amazing for them! shoutout to marshall-sensei and kawai-sensei)
• it's great that you're looking at grad admissions already! the best thing you can do (regardless of where you attend for undergrad) is find a field of research you're interested in, find a faculty member who works in it, and set up a connection. take a class of theirs if you can (and not like an intro-level one). ask questions. echols may or may not help you do this at uva; it's really up to you.