The cheaper concrete needs sealant reapplying every few years like you said, which I'd say makes it a relatively high maintenance option.
Bamboo has been popular and heavily used for 7-8+ years in Australia, and proving to be an extremely hard wearing floor. I'd imagine you wouldn't need it to last more than 15-20 years. Trends will probably deem both polished concrete and bamboo unfashionable by then anyway, and you'll desire something else.
FWIW there are people providing resin gloss PC for about $70 sq mtr but then you will have to re-seal in 4-5 years.
Just so we all know what we are talking about.