Hello On the Fence-There are spots in Glen Park that are subject to more traffic than most areas within the district, so it's not as if you can do no wrong there. It is smaller, so there's fewer of those streets in relation to the district. Bernal has a more diverse availability of properties. There's more upside available in Bernal and it's still slightly funkier / edgier. Glen Park has already become an established district of largely higher priced properties. There is rarely anything available of any size for less than $900,000. Bernal still has "room for growth". The weather in Glen Park is a bit more "docile" in that there's less wind, though maybe slightly less sun as well? That's probably something that could be debated.
Glen Park is closer to Noe Valley, one of the hottest districts in the city and Sunnyside, which is a district with good "upside" as well. It's also got the Bart Station.
Bernal is borderd by Interstate 280 to the east which separates it from the Bayview, Portola, Excelsior and Mission Terrace. Glen Park, Noe, the Inner Mission, and the Precita Park area are to the west and North. Not surprisingly, the higher priced properties in Bernal are to the west and north ends of the district as well.
I'd be happy to share other thoughts or discuss recent activity in both areas if you area interested in learning more. Have a great day-