The Photon seems to be fairly robust, but the 1g pegs are better replaced with more sturdy ones & you could add more guy lines if you wanted. They are pretty popular on mountain marathons. Like any tent under 1kg, it will have its limitations with strong winds, the choice of location & pitching correctly, can & will make a big difference.
Personally, I use the competition as I prefer a little more room, again for autumn/winter, I change the pegs. Its worth finding a shop that stocks them & getting them to put them up for you for comparison. It will also give you a good idea how much space you are going to get. Which isn't a lot for under 1kg.
Some of the Hilleberg (Akto) are very good & popular with lightweight walkers, probably a little more robust, but weight more.
Yes, PHD are expensive, but its top quality kit & British, spring/summer I use a Minim with liner, for autumn/winter, I used their 'build you own bag' service.
If you want quality, lightweight gear, it will cost you more