PS3 Firmware 4.88 released, do not update just yet

In a somewhat surprising (but not unheard of) move for a discontinued console, Sony have released a firmware update for the PS3. Firmware 4.88, released half a year after 4.87 (December last year), is

HFW 4.89.1 (Hybrid Firmware) Official Release

PS3Xploit and PS3 BGToolset Toolset are back, v1.2.006 adds

PS3 - 4.89 Update is Live! - Discussions / Details about the

New PlayStation 3 4.90 firmware update released, Page 2

PlayStation 3 Firmware Update Temporarily Grounds Lighthouse Beta

PS3 - 4.89 Update is Live! - Discussions / Details about the

PS3 Release: CFW 4.88.2 Evilnat CEX update

PlayStation Home Online 1.86 Running on PS3 4.88 Official Firmware

Why FERROX 4.88 isn't out yet? and should I wait for it or its not