A basic, tourist-class hotel in a sketchy neighborhood. But . . .
If you’re OK with that, the hotel delivers a clean, basic room with better than expected service and the neighborhood has culinary bonuses amidst the squalor. 
Room – simple and slightly dated but clean. Basic amenities (ironing boards, coffeemaker, flat panel TV) Beds are very firm – which I like. Sufficient outlets, but bring a long cord for your computer. I got this hotel via opaque bidding, which meant excellent value but also meant a less desirable room – the fourth floor has a pool and deck that wraps around the hotel – it means that I kept the blinds closed for privacy when I was in the room, since anyone could walk by. Also, in theory, access to your room is simple, the lock on the sliding door to the deck wasn’t particularly sturdy and there is no room safe. That said, I had no problem.
Bathroom – standard but adequate. Simple toiletries (shampoo, conditioner, lotion, soap) but I liked the lotion – it was quite rich on the skin. The shower in my room (439) had a variable showerhead, but the massage setting was anemic. 
Service – Better than expected. Check-in was speedy and almost brusque (I handed the man at reception exactly the material he needed without asking, so I could have been giving off the vibe that I wanted no chit-chat) After that, service was pleasant and accommodating. I made a few small requests for information and service and they were dealt with cheerfully and effectively by housekeeping. There was a brief wait at check out, but because I had pre-paid it was also very quick.
Wifi is free and the signal is reasonably good – occasional dropouts.
I did not use the pool or fitness center – Bay 1 Fitness is a block away and hotel guests have free access by showing their room key – I used that instead.
Neighborhood – this will be what makes the choice for most potential visitors. This area on Market Street near the Tenderloin is sketchy and filled with street people, who mostly go about their business but sometimes accost you. I’m a New Yorker and I still have to put on my game face to deal with it. If you don’t think you can handle that, skip not just this hotel, but this neighborhood entirely.
The upside is the Civic Center area has the Opera House and Symphony Hall, the Asian Art museum and the jewel of it all, City Hall (take a tour!) The Tenderloin (cross Market and walk up Larkin) is lined with simple storefront restaurants, primarily Vietnamese but also Thai, Burmese and Mexican, which are cheap and delicious. For all the sketchiness, it’s an eater’s paradise. Try Saigon Sandwich on Larkin and Eddy for awesome Banh Mi and El Castillito on Golden Gate off Larkin for really good tacos without having to trek to the Mission District. Many of these restaurants are inexpensive and cash only, so prepare accordingly.
So if you’re not timid or looking for a luxury hotel experience and the price is right, both the Holiday Inn and its neighbor the Whitcomb can offer solid value.