I researched TSM a little prior to the patch for making gold, but didn't care for the interface in the YouTube videos and found the setup instructions really confusing. However, come patch day, TSM was working, Auctioneer was not, and I despise the default AH UI, so I gave it a try.
Nice new interface made it a little more easier to set things up, though I think it still has a big learning curve. As far as crafting professions go, I like it because...
-- Doing a daily scan, I can auto-queue only the items that meet certain profit thresholds.
-- I can quickly buy the mats I need for crafting, be it jewelcrafter settings, scrolls, or off the AH.
-- I can post all of my auctions quickly at either a default value or undercutting competitors.
-- I have actually been able to participate in the glyph market, despite its vast size and complexity.
-- I can easily buy herbs to mill by the inks that I am missing, plus have some idea of what I am spending on the inks, so I can decide if I want to buy low-level herbs or current herbs. Though I am not quite comfortable with the prospecting version of that interface.
-- I can keep all my gold on a single bank alt, while still knowing what mats I need to buy off of the AH, but using the auto-mailer, I can easily mail them to the correct crafters.
However, not all of TSM's features are the best, at least imo. So once Auctioneer was updated, I also downloaded it, and can run both addons side by side. With the Auctioneer Suite, I get...
-- More control over disenchanting (accidently DE'd an epic staff with TSM) and suggestions on DE.
-- More responsive prospecting and milling.
-- Easier to use auto-vendor tool, though I lose out on TSM's auto-repair feature.
-- Simple to use interface for non-crafting auctions through the appraisal tab.
-- Easier to use search tools for non-crafting searches.
I also use Postal to open my mail, it seems to work "better", though I do like the timer and mail count that comes with TSM. And I found a new addon, EveryGoldToBanker, that lets me set my bank alt and the gold that I want to keep on each character, and automatically emails the rest to the bank.