I have owned both speakers, Rmhall, although not at the same time. I found the build quality of the Sierra 1 to be wonderful a the price (gorgeous cabinets) but didn't find the sound particularly moving or impressive. I liked the LSA's a lot, with the caveat that I had the "Statement" version with the ribbon tweeter, although I'm guessing that the overall character of the speaker line is similar.
I eventually moved on to other things, but here's a thread I initiated on AudioAsylum on the Statements:
http://db.audioasylum.com/mhtml/m.html?forum=speakers&n=294593&highlight=lsa+1+statement&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fauthor%3DGary%2520B.%26forum%3DALL%26sortRank%3DNone%26sort%3Ddate%26sortOrder%3DDESC
I eventually moved on to other things, but here's a thread I initiated on AudioAsylum on the Statements:
http://db.audioasylum.com/mhtml/m.html?forum=speakers&n=294593&highlight=lsa+1+statement&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fauthor%3DGary%2520B.%26forum%3DALL%26sortRank%3DNone%26sort%3Ddate%26sortOrder%3DDESC