I'm studying CCNA and i've just learnt about Reflexive ACL's. Just wondering how secure or insecure it would be to use an ACL in place of a firewall.
This was a LAB router that I would like to set up as my home internet gateway.
Yes, you can use a reflexive ACL but it couldn't possibly be as secure as a stateful inspection firewall. Since you are studying for the CCNA, you should build the lab network like real customers do. IOS has a real stateful inspection fw; I would use that.