I was browsing through the "hot" hubs on the Hubpages site when I wondered if the hubs listed on that page got any particular boost from it. It turns out they do. The hot hub pages (and "latest" and "best" hub pages) carry page rank of their own. Here's the pagerank of these pages@
Hot hubs page 1 - PageRank 5
Hot hubs page 2 - Pagerank 4
Hot hubs page 3 - Pagerank 0
Latest hubs page 1 - Pagerank 4
Latest hubs page 2 - Pagerank 3
Latest hubs page 3 - Pagerank 0
Best hubs page 1 - Pagerank 4
Best hubs page 2 - Pagerank 0
It's clear from the above that Hubpages gives you a boost as soon as you publish a new hubpage by listing you on their "latest" list. But this lasts only as long as you are on pages 1 and 2 of the latest list - once you are bumped off onto page 3 by new material, the boost fades.
Being a hot hub also has a lot of benefits if you are on page 1 or 2. Hot hubs seem to be those who are gathering traffic and comments fast. They tend to be mainly hubs published in the last four weeks. The "best" hubs are older and the ones on the first page all have a hubscore of 100.
It's definitely worth trying to gain "hot" or "best" status because you get a link from a very strong page.