The speed and the quality of the VUE renders differs from image to image. (Ok, I'm using VUE4 Pro which offers quite a lot more rendering options than VUE4 "Classic"). When using DoF even the fastest machine will put you in the situation of waiting for your render (not only drinking a coffee but going to the shop, buying it, bringing it up, cleaning up the coffee machine, cook your coffee, drink it and afterwards have an extensive dinner or so lol). But with with VUE Pro you are able to do your own plants and stuff - so, there are practically no limits for you.