This is from
http://www.mcmaster.com :
Aluminum Alloy Performance Characteristics
All aluminum materials are nonmagnetic unless indicated.
Corrosion Resistance
Excellent
1100, 3003, 5005, 5052, 5086, 6020, 6063
Good
6013, 6061
Fair
4032, 7068, 7075
Poor
2011, 2017, 2024
Forming & Working
Excellent
1100
Good
3003, 5005, 5052, 5086, 6063
Fair
2011, 2017, 2024, 6060, 6061
Poor
2007, 852.0, 4032, 6013, 5020, 7068, 7075, Mic 6, QC-7
Machinability
Excellent
2007, 2011, 6020, Mic 6
Good
2017, 2024, 4032, 6013, 7075
Fair
5086, 6060, 6061, 6063, 7068
Poor
1100, 3003, 852.0, 5005, 5052, QC-7
TIG/MIG Welding
Good
1100, 3003, 5005, 5052, 6013, 6061, 6063
Fair
5086, 6060
Not Recommended
2007, 2011, 2017, 2024, 852.0, 4032, 6020, 7068, 7075, Mic 6, QC-7
I looked at another chart, and 6063 aluminum's yield strength isn't as much as 6061, and 6063 isn't as hard as 6061. But, 6063 is better for working with, and 6061 is better for being used (if that makes any sense).