You can get 4.1 right now with TU if you have to have it now. Personally, I don't like waiting on Cydia to get around to retrieving my SHSH. To each his own.
It's better to use TU then waiting for Cydia to do it whenever. If you use TU to request it from Cydia server, it seems Cydia actually request them from Apple right then instead of at some unknown point which could be outside of available timeframe.