IMO, the Dell is a better machine for the money. It costs a little less than the Toshiba and you are getting a faster CPU and HDD. The only downside is the screen res. I feel that 1366x768 is a pretty small res for a 17'' screen. I'd personally rather have either a 1600x900 or 1920x1080 screen.
You are going to hear different things about quality depending on who is reviewing the unit. The Vostros tend to be pretty good since they are business class models. The Vostro 3700 actually has an Aluminum chassis, so it's going to be pretty durable.