I tried version 2.3 on my test machine, which has an old DLink DWL-G520 adapter. The new supplicant works as well as the old one did. There are problems, but I am pretty sure that the Supplicant has nothing to do with the problems.
I will try on more modern hardware sometime tomorrow, but the problems there are more basic than anything the supplicant does. The most serious problem is that I can find no way to turn on the radio. From what I have read, it seems that radio power is now controlled by ACPI, and we don't have anything that knows about that. I expect that Erik has the same problem.