Revisited and Up-rated Rated 4 out of 5 stars
Some time ago I posted a 2-star review of Session Manager. I've always had it in mind to give this add-on another go, and just recently I finally had the time to dig into it. Here are some of my original comments, along with updates.
ORIG: First, and most important, it failed to successfully import my more-complex Tab Mix Plus sessions, making a transition all but impossible.
EDIT: This was originally a real show-stopper. But my TMP sessions seem to be importing much more cleanly now (FF19). I have a feeling that the session save in TMP and the session import in SM have both improved, and converged as far as compatibility. At any rate, my previous issues now seem to be resolved.
ORIG: Second, I found the add-on over-complex. I liked the powerful features, but was confused by things like the appearance of multiple copies of my current session in the list, even when I had deliberately disabled the option to allow multiple sessions with the same name.
EDIT: I'm not getting the double entries this time. Either I found the mystical setting that cleared this up, or something changed in SM. I do still get numbers in brackets after the name of each session - e.g. "(1/40)" - I'm guessing that this means the number of windows and tabs. I wish I could disable this, as it is of no use to me, and I'd much rather have a clean display of just session names. Not a big deal, though.
ORIG: Third, there REALLY needs to be a way to export sessions to some standard format. Back to TMP format. To stock Firefox format. Or, best of all, to sets of standard bookmarks representing each Panorama group.
EDIT: I'd still very much like to see a way of bookmarking complete sessions (this is something I do a lot, and would love to have automated), or to Save As CSV, or something. Maybe there's an option I haven't found yet... but as long as SM works reliably, I can wait.
ORIG: If I could find a way to actually move my heavy sessions into Session Manager, I'd up that to 3 stars (and become a regular user). That would leave 2 more stars for the other issues I've noted.
EDIT: Many months after writing my original review, I have now managed to get my sessions working. I've been using SM regularly for a couple of weeks with no issues. But I'm bumping my rating to 4 stars, for at least two reasons. First, I like the ability to quickly save over my current session, which I couldn't easily do in TMP. In SM, it takes one keypress and a double-click. (I have a feeling I can probably do it with a single keyboard shortcut, once I have time to figure it out.) Second, I very much appreciated the way my Firefox state was restored when my system crashed today. All tabs in place, all tab groups intact, all 'faviconized' tabs as I left them. Bravo! TMP tends to mess up my layout, in this kind of situation.
I'll hold back one star for the minor tweaks I'd still like to see. But in reality, I'm hovering around a 4.5. I still think the UI could be tidied up a bit, and documented better. (This is a very complex and powerful add-on, and I don't have unlimited time to scour forums.) But I've kept SM in mind since my first attempt, and it has ultimately won me over. Whether that was a learning process on my part, or an evolutionary process in the software, I can't say. I still wouldn't recommend SM for a total novice, but as a heavy Firefox user (168 tabs in my current session), I'm making it part of my core add-on set.