My husband, dog, and I booked a room at Surfside because it was the only place with availability three weeks before the 4th of July holiday weekend. We feel we lucked out (despite the inflated holiday rate - can't blame 'em) because Seaside's 4th of July fireworks are billed as the biggest on the OR coast, and the cars still at a standstill at 2 a.m. proved them right. Do NOT drive into Seaside on the 4th of July unless you have a place to stay - you'll never get out.
About the Surfside: it's a dinky little motel with small rooms, but the rooms were recently renovated and actually look quite nice. There's no daily room service, but the VERY nice manager will provide anything you need if you simply ask. The two block walk to the promenade is key - EXCELLENT proximity to the beach and restaurants on Broadway. The beds make a creaking sound when you sit on them or roll over - a bit annoying, but they're comfortable enough. We appreciated the free wireless internet access, ceiling fan, and mini 'fridge. Walls are thin, so you can hear activity in the room behind you.
Note to the owner: an additional mirror in the bedroom area would be helpful when one person is using the bathroom (and it'd make the space feel a little larger, too - bonus!).