For what its worth, I've used my 436hp for a few weeks now. I've found that connecting the card with a the USB cable works pretty well. Unlike the PSR800 which I believe only transfers at USB 1.1 speeds, the 436hp appears to transfer at full USB 2.0 speed; I've had no issue with errors. I've not found it read/writes any faster when removed and connected to a high-speed card reader.I haven't got the 436hp yet cause on back order hope to be shipped out this Fri by HRO. I see the sd card is underneath the batteries which I don't understand. I thought it would be on the side like the PSR800 is. I may get another 4 or 8 gig card for back up cause I don't like transfer the files over the cable cause get errors. I know this for sure I won't be charging the batteries in the radio.
The microSD card holder mechanism is a little flimsy IMO (especially when I've tried to change the card without my strong reading glasses and good light!), so I only remove/change the card sparingly.
I always charge external to the scanner. I've can get 6-8 hours (POWEREX 2700) with backlight on, though a generally connect to a USB power source much of the time (both at home and mobile). And I keep one or two sets of spare charged batteries.