The new EBL USB-charged 9V batteries

Does anyone have experience with these and know how much current they can source? In particular these:

http://www.eblmall.com/product/ebl-usb-rechargeable-9v-lithium-batteries-5400mwh-long-lasting-li-ion-batteries

They seem to contain a LiPo cell, USB charging for it (inbuilt microUSB connector!) and a 9V boost converter to output constant 9V. They are rated at 600mAh (5400mWh @ 9.0V), and look to possibly be very handy for higher current circuits if the internal boost converter can produce high currents.

Couldn't find a datasheet though,

I've ordered some and will investigate, just wondered if others had experience with them and recommended them for use with motors for instance (hence this part of the forum). And indeed for analog electronics (is the boost converter noisy?)

I know they also make "9V" LiPo batteries which are just 2S LiPo package (ie 7.2V batteries in reality which come with a special charger). Those I'm less interested in as the output voltage is low and droops, but still they may be of interest for motor operation and certainly should have decent current handling.

watt hours to other things.

Not much.