WiFi Shield Reliability

I got around some WiFi Server problems described in my previous post ( Official Wifi Shield Disconnect and Reconnect Problems - Networking, Protocols, and Devices - Arduino Forum ) by simply re-structuring my protocol and using the controller as a client and not using WiFi Server.
But now, I still get random disconnects. The controller just goes zombie. Sometimes, not even a power cycle can reset the board, so I have to do that multiple times until it works. Sometimes, I noticed that although power was connected, not even the arduino "Power" status LED was active. How is that?
Apart from that, WiFi.connect() never times out when using timer libraries. How can I fix that?

I really need my setup to work more reliably as I can not afford switching platforms. Does anybody have an idea?

Thanks in advance.

kind regards,
kamo