Google Pixel gets the Android updates, faster than any other smartphone. Hence, if you have a HTC 11 with Android 7.1, when Google launches Android 8 or Android O by the end of this year, HTC 11 may not get the update immediately.
Second reason for me to recommend Google Pixel is the unlimited storage space offered with every Pixel account. Therefore, you need not worry on cloud storage space. Whatever space you would like to free from the smartphone, can be pushed to the cloud storage.
Where HTC may have an edge over Google Pixel is the faster performance, thanks to Snapdragon 835 as against the 821 in Pixel.
To conclude, if Android update and unlimited Google Cloud storage is not that important, you can pick the HTC 11. Or else, Google Pixel is still a good choice in 2017.