My friend Natalia and I stayed the last week in June at an apartment at Voznesensky 20 near the Maryinsky Palace. It was quite roomy and comfortable with two bathrooms, a kitchen and dining area, AC and internet and within walking distance of the center. The security was good, it was clean and had maid service. Make sure that if you are asked for a deposit when you arrive that you get a receipt. Being fatigued at arrival we failed to ask and never got our $100.00 deposit back.