I still use my T420s as my daily driver laptop. I'd like to get something with a better screen and faster CPU but it's still reliable so it's hard to justify.

I still use my T420s as my daily driver laptop. I'd like to get something with a better screen and faster CPU but it's still reliable so it's hard to justify. What batteries have you had good luck with? My main and ultrabay batteries are both down to around 50% of original new capacity now.