I thought they look great. The white phone is absolutely gorgeous. What is sucking in my mind is the contrast between the 8 and X's form factor. The X looks amazing and makes the 8 porky and outdated.
I've owned the 3G, 4, 5, 5S, 6+, 6S+, 7+, and the 8+. Every single iPhone has looked premium (with the exception of maybe the 3G/3GS (but, for the time, it was very nice looking). The 8+ looks phenomenal, and really super expensive.
There's literally nothing about the 8+ that looks cheap.