To be honest, as I checked, 16 port cards are really expensive....
Personally I'd recommend similar LSI chipset - just with 16 ports, for example 9201-16i may be between $400-$500
If you'd have an other free PCI express x8 (or x16) port on your motherboard, the most economic solution would be adding an other same 9211-8i card.
If you check other manufacturers and you do not use RAID, avoid Adaptec non-RAID HBA cards. While Adaptec RAID-type cards work great and complete hard disk status can be detected and monitored by Hard Disk Sentinel - this is not true for their non-RAID cards (HBAs).