Comodo and Emsisoft Online Armor are very good firewalls. If going free some that you can also consider are Privatefirewall. The thing with OA is that it's noisy and throws a lot of pop-ups much like the version 3 and 4 of Comodo. As I compare both OA and CIS, Comodo is much more tamer now.
OA is still noisy that is why it is important to let it scan your pc during the installation proper and make sure you let it finish. Last time I tried the QA free version it does not have the capability to import/export settings. So you'll have to do it all again when the need arises. Alerts are further tamed when upon successfull installation you put it on "Learning Mode" and open/run all your programs so you'll have the chance to see the pop-ups and make a rule for your programs application.
Security wise it's a hands down choice (on my preference). The GPCode and it's variants plus the Stuxnet and other ransomewares are blocked with Online Armor default settings while in Comodo you'll have to set it to include the *_CRYPT and /Device/KsecDD in D+ Protected Files and folder. Comodo sandbox needs a lot more work. If you sandbox browsers through the firewall then you can with both(OA has RunSafer). Only OA's is much better because if you cannot go printing something in .pdf while in a Comodo sandbox browser.
In paid firewalls OA Premium ver5.5 is still (imho) one of the best alongside Outpost Firewall Pro ver7.5.3 and of course CIS Pro ver5.10.
Of course personal preference and how you feel when you have tried it is king. So I'd suggest you try both for a week and then gauge what you like best. When using a new set-up, I'd image my system first so when I wanna go back to the previous it'll be a synch. I also save settings for those firewalls so when I re-install I'll just import the config file I saved. Beats setting it all up again
Some interesting links that I found when I started using Eset with Comodo. The post shows how OA/Outpost/Comodo is superior to the firewall of Eset Smart Security ver5(well on the problem stated only).
HERE 1
HERE 2
Might be a good thing to exclude you other security applications in the firewall exclusions list in OA or place it as Trusted in D+ / CIS firewall. That way conflicts will be from minimal to none.
Emsisoft Online Armor forum
Official forum download page for CIS ver5.10
Help-CIS_Comodo forums
Privatefirewall
You can get a bevy of good insights (pro/con) for Privatefirewall settings/tweaks at Wilderssecurity. A guy there from Hawaii "Bellgamin" is there to help.
example Wilders_Privatefirewall
Outpost Firewall Pro forums
Manny Carvalho is there at the OP forums if you have some questions about tweaks.