My N900 was very weak in the terms of battery life. Even with a new, genuine 1430 (I think, I can't check now, my swap is on my SD ) mAh battery, I needed a mobile power bank or a charger in the middle of the day if I wanted to use it's capabilites. Default CPU speeds or OCd to 500-1000 MHz doesn't really matter.

LG Leon (1900 mAh) doesn't need any power for at least one day, two days are possible with intermediate use.
And I mean this with constantly online mobile data (LTE), 2-4 hours of music playing, and some Messenger usage, checking bus schedules with GPS and so on.. it's a whole new dimension.. N900 just old.
As a phone, and phone only, it's ok, as a smartphone, well.. questionable these days