What were the problems with the previous site? I used it without major problems.
Wouldn't a browser plugin require you to actively be using HN, or at least have a tab open? Getting an email notification four hours later that someone replied to you on HN, so you may want to take a look is nice (if you don't want to be a slave to HN, don't check your email as often or don't deal immediately with this email).
Additionally, in a browser extension, there's then a lot of people grabbing the comment history rather than a single program, which necessarily puts a higher load on HN.
Wouldn't a browser plugin require you to actively be using HN, or at least have a tab open? Getting an email notification four hours later that someone replied to you on HN, so you may want to take a look is nice (if you don't want to be a slave to HN, don't check your email as often or don't deal immediately with this email).
Additionally, in a browser extension, there's then a lot of people grabbing the comment history rather than a single program, which necessarily puts a higher load on HN.