I have used CBS for a number of years and their product is surprisingly good, it is however getting expensive to the point which I would actually rather see people boycott them all together so they drop their price or make the move to free.
I have used Yahoo and ESPN as well although I am not using either this year. I think the biggest drawback to Yahoo is the league structure. It is harder or near impossible to customize your league on Yahoo at least not to the level of customization that ESPN and CBS offer. When using ESPN I found that there updates were often erroneous and the real time data lagged. Again it has been a year since I used ESPN so perhaps they improved their product. CBS is very easily customizable and real time data streams almost exactly with live action but again it has become expensive. As far as the upgrades you are looking to implement on your league this year I think CBS is the only site to support a real time auction style draft. It is a nice feature but any league worth its salt should be able to host a chat on yahoo, IM, or other service and run the auction and just upload the data.
If you are starting a new league, CBS is running a promo where new leagues are 1/2 price, so it does cut the cost considerably:http://cbssports.com/ref/38747310
In all, I don't think you can go wrong with any of these sites especially if it is all you know. The grass is always greener though.