I use OpenMTP in MacOs, a free open source software that is reliable when transferring between PC <> SP3000. I found it to be the best option because it shows the progress for each files and we can identify problems on the files if it occurs. Plus it works with any android devices including any android based DAPs or phones.
I found it pretty annoying for AK to remove SD card often because the case need to be removed all the time to access the slot. I always access my library often and I want to keep my SP3000s body as clean as possible

. Hence I use the OpenMTP to transfer my files but also kept an adaptor ready all the time just incase.