I found VWS to be using a lot of resources, both memory and CPU, and the VWSaprs bolt-on utility necessary to upload to CWOP was also somewhat cumbersome. While that shouldn't be too much of an issue for most newer desktops, it still a consideration of mine.
I have Cumulus uploading to CWOP, WeatherUnderground, PWSWeather, WeatherBug, and WOW. It runs silently in the background. You can mouse-over the tray icon for a quick peek at the OD temp, wind speed and direction. Plus I like the look of my customized Cumulus data display panel.
While I'm at it, WUHU also runs quietly uploading to AWEKAS.