Replacement battery recommendations?

[basement_blues]

I was looking around the forum (and the general Thinkpad forum) for postings about which replacement batteries are reliable. Anybody know of any sites where someone tested different companies' batteries against each other (for overall life, not length of each cycle)? If not, maybe some personal experiences with AGPTEK or Anker or other brands?

[RealBlackStuff]

Nearly everyone who bought a non-IBM or non-Lenovo battery has fallen flat on their face, many sooner (only weeks) rather than later.
The only known working alternative came from Boston Power Sonata.
Even those battery cases have some problems, because some of them are slightly bigger than the originals (but do fit at least).
Also, they seem to be rather rare, only made for the likes of T6x/R6x, T500/W500. YMMV.
See this: http://forum.thinkpads.com/viewtopic.php?f=2&t=81968