Good….the Proporta 3400 turbocharger battery is good and for under £35 represents decent value. I can recharge my iPod Touch twice over on a single charge and it comes with a carrying pouch and selection of “tips” that fit different phones and gadgets. I can recommend it whole heartedly as a portable battery charging bit of kit not just for Apple stuff but for micro and mini USB devices.
Crap.…the Kensington iPhone Battery pack charger. This actually costs a couple of quid more than the Proporta yet struggles to give my iPod Touch anything more than one full charge. The capacity is obviously well below that of the Proporta one which is surprising given the cost. I bought a real cheapo iPhone charger, one that you just stick into the iPhone bottom dock, off Amazon about a year ago for £12 and it lasts as long as the Kensington one which just emphasises how disappointing it is.