Well, my almost an year and a half old Dell Inspiron 5558 gives me 5 to 6 hours (gave 7 to 8 when new) with just web browsing. I don't think that's all that great.

And mind you, I am the kind of person who has managed to accrue about 13 months of hard disk head flying hours according to the SMART stats so the battery isn't exactly in a good condition.