Both routes are up and over the mountains, but when we travel west through Colorado its I70 if were just passing through. Now if were there to visit Co and have a extra day or two we love to travel Rt50 a take the views in and snap some pics as we drive along streams and climb to the top of Monarch pass stopping at the top for a 10min break at the top to look at the views.. Oh its a climb to the top in 2nd gear and going down its the same, but no rush just take your time and watch the brakes going down any mountain top can be nerve racking just drop a gear or two and dont ride the brakes if they start getting too hot we pull over and chill for 5mins or so...To us Colorado is all about the Mountains and their views...Enjoy