And just as an aside here - if you want beautiful outdoor scenery then I think Terragen2 still takes some beating. I just couldn't be bothered with all the hassle of trying to plant objects in the right places, so I rarely use it any more and do everything outdoors in Vue instead.

I think it all depends on which render engine suits you and you get along with the best. Trouble is trial and error sometimes gets a bit pricey...