I brought the Anker PowerCore 10000 Portable charger to keep my phone topped up between overnight charges, due to a certain game which requires you to catch them all but makes this difficult by eating though battery life faster than Usain Bolt does the 100m. Since my partner plays this game as well i also brought the Aukey Quick Charge 2.0 (10400mAh) so can directly compare the two.
Size - it really is one of the smallest portable chargers i've seen - especially given its 10000mAh rating. It is smaller than the Aukey, not by much but it is noticeable. In fact it is smaller than a lot of portable chargers half its capacity. True credit to Anker for fitting so much into so little here.
Construction - Build quality feels solid however it does seem to mark easily. However it comes with a protective drawstring pouch so if you use it you can avoid this and keep it looking new. The Aukey seems well built too and does seem to hold up against scuffs and marks better than the Anker, which is required as this did not come with a protective pouch.
Design - The Anker does look a nice piece of kit with its smooth black finish and its blue 4 light system for showing remaining charge. However because the blue lights are on the side it means completely removing the device from a pocket (and a pouch) to see how much juice you have left. The Aukey has a silver on white finish which i feel looks a bit cheap, however it too has a blue 4 light system for showing remaining charge but in a much better location at the top of the device. Due to this id say they were about even design wise with the Aukey sneaking it if you prefer silver and white to black.
Ability to Charge - The big one and the reason for buying any portable charger. In this respect the Anker is faultless and seems to perform above its 10000mAh rating. In my experience it can recharge a phone 3 - 4 times, depending on the phones battery specifications. On one particular day 4 of us needed to use this and as such was in use the entire day. It managed to keep all 4 phones alive the entire day - no mean feat given the already mentioned game can deplete a battery in a few short hours. The Aukey cannot match the Anker here. Despite the extra 400mAh it just seemed to drop charge like it was going out of fashion and i'd say you would be lucky to get 2 - 3 charges out of it. If you are away from a socket for more than a few days, power more than 1 device at the same time or need to power a tablet or laptop you will want to look elsewhere as this just wont cut it for that. If you want the ability to charge a device while charging this you will also need to look elsewhere as well.
Time taken to charge it - Again the Anker performs well here. While i haven't done timed tests leaving it to charge overnight should get you back to full from almost any level of remaining battery. The Aukey really struggled here and took significantly longer to get back up to full charge which isn't really acceptable when it doesnt seem able to give as many charges as its quicker charging companion.
Price - when purchased this was £16.99 which i feel is a bargain for what you're getting (currently £23.99 at the time of writing). The Aukey was on a flash sale and only cost £11.99 (currently £17.99 at the time of writing) so is much better priced.
If you are looking for something small, portable and able to recharge your phone 3 - 4 times then you wont do any better than this. Would easily keep a phone topped up over a long weekend away camping or partying at a festival. It is overkill for what i brought it for and is more than enough to keep a phone going between charges on your quest to catch them all, however given just how small and light it is compared to its rivals it does this job well. The only downside is that you cannot charge a device while it itself is charging but at this price point you can forgive it. Thoroughly recommend.