A surprisingly cheap place with no/few reviews is a gamble.

If it were near the Metro, they would mention that on the website since it's an important selling point for many people and would let them charge a higher price.

Sixteenth Street Heights goes as far south as Spring Rd, which would put you right next to Petworth Metro station, and a lot of people would mistakenly call that Petworth, all of which adds to the likelihood that this place is further north and not near the Metro.

You'll likely have to rely on the bus, which actually isn't too bad. Frequent service on Georgia, and an express line available.

In terms of safety, being further up Georgia is actually way better overall, since Petworth Metro station is the site of almost daily violent incidents.