[...] but can someone offer information on what's new in this version?

I quote:

[2010-11-12: REVISION 1616]

[CHANGED] Disable interactive input support as this is unfortunately causing too many problems on Snow Leopard. Ticket 75950BCB.

[NEW] Set DisableClipboardPrecomposing to 1 to disable the precomposing introduced in r1589.

[NEW] Included Make bundle among the default bundles.

[FIXED] Solved problem with broken application after software update. Ticket D8B9A720.

[FIXED] Correct the CSS link in the printable version of the manual.

[CHANGED] Change next/previous file tab key equivalents to shift command [ and ]. This has become the de facto standard.

[FIXED] Improve key event deciphering when running on 10.5 or newer. This should fix problems with the Qwerty / Dvorak hybrid.

[FIXED] On Snow Leopard TextMate should no longer lose last used folder for Save As. Ticket FEE58154.

[FIXED] Truncate really long menu item titles. Ticket 8BBEF40A.

[FIXED] Add missing CFBundleIdentifier which was lost in last update. Ticket F970873A.

[CHANGED] Update use of selectRow:byExtendingSelection: to avoid deprecation warning in console.

[FIXED] Don’t use undocumented API for save panels. Ticket 45963BCA.