+1 for Android as well.
As a developer of mobile applications (both in native and web), I can speak for the viability of the newer android devices, especially as an emerging platform. My company's bottom line would be seriously hampered by not supporting this significant demographic. I cannot speak for Kindle Fire, given that while it is an inexpensive alternative to other tablets, the general commitment to housing a dedicated web platform hasn't entered the realm of competitiveness or even web readiness that is demanded of an accepted platform. To put it bluntly, the platform is a glorified book that is non-standard, feature-weak, not enough people with money use it, and there's no incentive to change that (similarly, we're not working with blackberry). You are wise to pick your battles.
Of course, your development team knows this, and is quite keen on reasonable scope support with respect to the bottom line and the very sustainability of your organization. I've been writing my own web app that latches on to Hero Lab's export, performing a scrape of the HTML statblocks and character sheets, and then using it as a malleable web application that works fine in chrome (because god help anyone who uses something else

). This has helped me out tremendously, as all the information that is reasonably organized within your application can then be accessed without much ceremony. Basically I make the html docs a day or so before the session, and my smartphone becomes an interactive note card for my statblocks during the game. Plus, it gives me the ability to work around many of the short-comings and known bugs within Hero lab (not that I'm faulting you there, because any sufficiently non-trivial application will have bugs). As a game master, this has turned a fun toy into a powerful tool. I'd be happier if the HTML you exported were more... stylized of course, however this works for now.
That, of course, begs the question, if I'm capable (as one person) of writing a web application (as in plain ol' html, css, and js) in my spare time that can overcome these shortcomings, what's to stop someone else from doing the same? If the source material is available through the online PRD, the value added by hero lab is limited. Respectfully, I caution you not to neglect this emerging demographic while you can maintain a competitive edge. You have a fine product, but an inaccessible fine product is no product at all.