I've recently (May 2013) done some tests on particular situations like a chain of tag relations where t1 is included by t2 which is included by t3 ... which is included by tN, with N being 40. The objects managed were 8352! The experience showed a very quick response time of 10.739s when Tagsistant was asked to:
ls ~/myfiles/tags/t1/t2/t3/t4/t5/t6/t7/t8/t9/t10/t11/t12/t13/t14/t15/t16/ t17/t18/t19/t20/t21/t22/t23/t24/t25/t26/t27/t28/t29/t30/t31/t32/t33/ t34/t35/t36/t37/t38/t39/@
After the first run, issuing the same query again got answered in just 3.598s. This query if of course very suboptimal since gives the same results of ~/myfiles/tags/t39/@, but my goal was to test how Tagsistant could behave under a lot of tags in the same query. The total files returned by the query were 937, which generated as much getattr (stat) calls to get result data (size, owner, permissions).
I've successfully tested Tagsistant on repositories containing 100G of data.
I hope this quick introduction to Tagsistant 0.7 will be enough to let you experiment with the software and find it useful. If you have any comment, I would be very happy to hear you.