it's not as small as the tiny 220ex (which is pocket size) but compared to the 580ex it is a lot smaller, and still fits in a jacket pocket. The 430ex has an impressive-for-it's-size guide number of 43 (I explained guide numbers on my 580ex review) but all you need to know is that it's only slightly less powerful than it's bigger brother and much more powerful than the 220ex- and it comes in a small package and is fairly affordable compared to the 580ex.

The extra power of it's bigger brother comes in handy when shooting bounce off a high ceiling, or when trying to overpower the sun, but for casual use or for when you can raise the iso the flash is powerful enough for most situations.

it is a great flash to start off with, and can be used as a wireless slave (not a wireless master though, for that you'll need a top-of-the-line 580 or older 550ex). My recommendation would be to use this flash in conjuction with a 550ex, both are affordable and that would give you a 2 light setup with wireless capability for less than the cost of a 580ex.

Build quality is great, nothing feels cheap and everything is logical and easy to adjust (not that it matters if you just use it on automatic mode).

If you're on a budget and can live with the reduced power get this (or if you just want a smaller flash), get a 550ex if you want more power/wireless, and avoid the off-brand flashes from sigma etc, they're junk.