I have purchased some items from Leisure Pro - and my sister (recently certified too) purchased her first bc/reg combo from them (they have several packages). They were all just fine.
However.... wherever you purchase, make sure you read their statements about return policy and warranty issues. Some big online retailers may not be "Manufacturer authorized dealers" for a given product, and therefore, the mfg may not honor warranties of items not sold by their dealers.
In those cases, the online seller, LP does this for instance, offers its own warranty. Each item from each mfg may have a different situation with its warranty, so please be sure to check it out. And of course, you want to buy from a company you think will be around long enough to honor the warranty!!! (so, there's a risk involved).
I have also ordered from Divers Direct online - and been to their stores in the Keys. No problems there. They changed out my Low Pressure inflator hose and added a console while I waited in Key Largo.