There are two issues with extended text entry on an iPad: the lack of tactile feedback, and the tradeoff of typing and viewing ergonomics. They've added tactile feedback, but you still need to keep the iPad near horizontal in order to type on the screen.

I've got a bluetooth keyboard/case/stand made by Zagg (branded by Logitech), and although I haven't tried the TouchFire, I would prefer my current setup. A side bonus is easy accessibility to all characters—I don't do any programming on this, but I write LaTeX and Markdown regularly, so making curly brackets or asterisks easier is a nice plus. I thought I would benefit from the increased screen real estate (when using a bluetooth keyboard, the on-screen keyboard is hidden), but in practice I don't think it actually helps.

Here's a non-affiliate link to the product I've got: http://www.amazon.com/gp/product/B0054JE706

And here's an affiliate link, if you're into that sort of thing: http://tinyurl.com/dy4skxe

edit: You can't really see how the product is also a case on the Amazon page. Here's the product page, in another non-affiliate link: http://www.zagg.com/accessories/logitech-ipad-2-keyboard-cas...