Price isn't necessarily an indication of better quality, if the reviews are decent and the parts look good then have a go - I just linked to the store that I have personally ordered from in the past.

For Alu, yes upcut is definitely what you want as chip evacuation is vital. Ideally one would also be using compressed air (with added bonus points for mist coolant) with a nozzle aimed to blast any chips out of the way.

I initially bought Downcut for some closed cell foam I was machining for custom cases/tool trays. They are mostly of use in softer materials where the top edge can be a bit rough with an upcut bit. Compressed air or a vac shoe can help with chip evacuation there.