• Bamboo Expands & Contracts
Bamboo, like wood, moves in response to changes in temperature and humidity and can't be restrained too tightly once installed. Some bamboo countertop and plywood manufacturers give detailed instructions for installing bamboo countertops. If you (or your installer) don't pay close attention to them, you might have problems with your countertops down the road.
This characteristic also plays a role when sealing the bamboo. Your bamboo countertop should be sealed in a "balanced" manner meaning that the top AND bottom of the material should be sealed with the same number of sealer/finish coats. Again, pay close attention (or make sure your installer does) to the installation instructions provided by the source of your bamboo countertop.
• Do Your Homework
Good bamboo (durable and high quality) comes from reputable sources that harvest bamboo at the right time and use quality adhesives and finishes. When you investigate various makers of bamboo material check to see what information they provide about these aspects of bamboo sourcing. Is the bamboo harvested around 5 years of age (give or take a bit)? How much information do they offer about the types of glues and/or sealants they use? Are they safe for food-prep and do they contain any formaldehyde?
The bottom line here is that you don't want to get just any old bamboo from Joe's bamboo shop. Find out how long the maker has been working with bamboo and how well they stand behind their product.
Find out what kind of warranty (if any) comes with your bamboo worktop or the plywood you buy to have made into a countertop. What you want to look for here is some form of coverage against delamination and separation since bamboo worktops are a glued-together structure. As with all product warranties, make sure you read the fine print and understand both what is and isn't covered.
• Sealing & Finishing
Think about how you plan on using a bamboo countertop, whether as a 'standard' countertop or like a cutting board. These decisions will affect the type of bamboo construction (grain orientation) as well as the kind of sealer you choose. Good sources of bamboo countertops and plywood typically provide information on the types of sealers they provide and/or recommend.
Also remember that some sealers, like mineral oil, require more maintenance in terms of repeat applications to maintain and protect the bamboo surface. And don't forget that Tung oil, although a good sealer, is derived from nuts and may cause allergic reactions as mentioned above.
• Larger Countertops May Have Seams
Because bamboo material used for countertops comes in finite sheet sizes like plywood there are limitations to how much area can be covered without seams. Seams might not be a big deal to you but just keep in mind that if you have a large kitchen island you want to cover that exceeds standard stock sizes, you may end up having one or more seams in your countertop.