I never expericed any problems with WiFi on 2.0.0 / 2.0.1 etc. But I have noticed that the 2.1 software can take up to 5 mins to lock onto a WiFi signal (unlock your phone from sleep mode). In the meantime it uses 3G and drains the battery faster. WiFi was something that wasn't broken, why mess with it !!! Apple are worse than Microsoft for bugs now.