I just rode 115 miles on my Lambert yesterday, S3X hub with 48/14 cog. A lot of fun, though tiring by the end of the day.

I have not done the freewheel thing; it is a simple conversion, just take the locknut, spacers and cog off the driver and screw the freewheel on. Make sure your freewheel is removable; some of the cheap ones are not. You don't need a locknut or anything; you can use a spacer or two to tweak the chain line a little bit but you won't have as much room to play with as you do with the fixed cog.

I don't know anything about the wheels you ask about, but by way of an answer: I strongly recommend learning to build your own wheels. It's almost as much fun as riding them, and you can do it while drinking beer and listening to the radio. This opens up the world of reusing old hubs and stuff, which are cheap and plentiful and generally reliable.