As the features of the RV220W currently are the best for my purpose (WLAN, SNMP, IPSec VPN, 6in4 tunnel), I decided to not return the unit.
The 1.0.2.4 firmware is an improvement, but the unit still has many smaller or larger issues.
I have compiled the official issues from the release notes (16 of 21) and those I have observed (currently 23) in a bugzilla at
http://bugzilla.jth.net
Please, feel free to add new ones or solutions to old ones.
I consider it a bad decision of Cisco not to cooperate with me about documenting and solving the bugs I have found.