I just finished HSoA an hour ago. Its a great game. Top 15ish for me. Desert Stalker is more quality. Renders, sound, UI, writing, all is a little bit better. It looses some points with the sandbox. If I had to rate 0-10:
HSoA - 8.2
DS - 8.9 (without sandbox probably 9.4)
Both are great but Desert Stalker is way more polished. All (!) the renders and the story both fit perfectly within the theme, which I think is pretty impressive given how niche a post-apocalyptic renaissance Egypt actually is...