I would definitely stay away from bamboo, and most especially for a kitchen and even moreso if you have a dog. It does not hold well at all. I used to be a big fan of it...until what I saw what it looks like a year or two later.
It dents and scratches very easily, and it shows it more than hardwood. It doesn't hold up to water well at all. I have seen so much damage for minor issues...things that are unlikely to impact regular oak. Most are very low quality and use a cheap water base poly and this is why they don't hold up well. There is a reason it's so cheap. If cheap is you main motivation, go for it...and know that you will need to replace it in a few years.
Most can not be sanded and refinished, and no I wouldn't bother to add a coat of poly. That will actually make it worse and take off some of the aluminum oxide.
If you were to do it, go for more expensive strand woven. That is the only type that has a chance. It can not be refinished. Avoid carmelized bamboo. That gets the color from heating it and that weakens it even more - makes it softer. Avoid stains as those do not hold well and show scratches wi/ 6 months.
When I do hardwood in kitchens, I usually do unfinished hardwood that is refinished on site so it's coated w/ poly. Oak tends to work well and the strong graining hides the scratches. I'm not a big fan of prefinished hardwood for kitchens as the microbeveled edges often to do not have poly and hence less protection.
You might want to check out this post:
Does hardwood flooring for kitchens make sense?
http://theflooringgirl.com/hardwood-flo ... sense.htmlDebbie Gartner, aka The Flooring Girl
http://TheFlooringGirl.comWestchester County