We have just transited the canal, so having experience on both sides I recommend provisioning
as much as possible on the Colon side. Use the free bus from Shelter Bay and either arrange the free Rey's van back or get a $25 cab back. On the Panama
City side you can find most things you want but couldn't find in Colon, but everything is spread out and there is a lot of hassle getting it to your boat. The shopping
is better on the Panama City side with a Costco type store and many big stores if you have plenty of time and patience. I found it very easy with the dock
to load up on the basics at shelter bay while waiting for our transit day.