I understand your frustration, however there is a very positive reason why RS232 is the more stable download option.

ALL large system controllers use RS232 due to its very stable ability to download data, home automation systems still rely on RS232 for this same reason, same as car engine management systems. Look at GHL as not a basic aquarium controller but an automation system. You mention Neptune, the product has very little comparsion to GHL other than its use in aquariums.

My advise would be to get cheap USB to RS232 converter and you will never have issues like this again.

For the USA market we are looking at supplying these with kits but this is about 3 months away.