What is currently the best Firewall device for medium and Enterprise Companies ?

cisco asa5500series and fortigate for enterprise firewall

Fortigate, Sonicwall firewall is good one for SMB.

The best Firewall device for medium and Enterprise Companies is Cisco ASA 5500 -x series Firewalls.

Check Point Software, Palo Alto Networks, and Fortinet are all market leaders in the next-gen firewall market.

Palo Alto, Checkpoint, Cisco ASA, these are usually used in medium and enterprise.

As far as i concerned it depends on the reuirement of reliability and complexity of algorithm even if its medium or enterprise. 

if you want best security level it is cisco FirePower but if you want a good security and the best and real appilication level firewall it is paloalto.

for me i rate  cisco ASA  and palo alto

If you have big network or moderate level of network than you can use Paulo alto or fortigate please don't prefer cisco ASA becuase its being obsolated gradually from network industries so it's better to have better and upgraded else old technology....

Check  point is a option too , but it might be costly.....

Basically It depends upon the requirements of the organization and approved budgets. It really does not matter what product or series we use wheather its Cisco, Paloalto or Fortinet for network security.If they need UTM then they can choose Palo alto or checkpoint as market leader or Fortinet as a budget product if its firewall then Cisco.Features may very product to product or model number but its totally upon the companies.

Cisco ASA 5500-X Series with FirePOWER Services.

OR 

Palo Alto 

if need  cost-effective Fortinet

"Cisco ASA 5500 , Palo Alto"