Though The Ring (next on our list) actually takes the spot above Hotel Topazz in our "best luxury" roundup, Hotel Topazz holds the number one spot here, thanks to a truly boutique ambiance created through a focus on design, service, and style. With a quirky exterior and Art Nouveau interiors, this hotel features plush furniture and rich colors. There's no fitness center or spa, but the 33 rooms -- with marble and chrome bathrooms, unique windowsill seating, and free Wi-Fi -- are truly luxe.

For a boutique property, The Ring is packed with amenities; there's a full spa with a fitness room, a wine cellar with private tastings, and a fine-dining restaurant with an adjoining cocktail bar. Rooms, outfitted in neutral tans, greens, and browns, feel a bit bland for the level of luxurious, but they are spacious and sleek enough, and all have espresso machines.

This design-centric property opened in late 2013, and guests immediately notice the modern touches, particularly in the sleek rooms that come with minibars stocked with free goodies, like wine. While features like a spa and fitness center are missing, highlights here include a delicious restaurant that's popular with locals, as well as an on-site cafe that bakes its own pastries and roasts its own coffee.

The 45-room Hotel Altstadt is located in Vienna's vibrant artist quarter, and it embraces the neighborhood's vibe with features like a vast private art collection and large, individually decorated rooms. (Some are significantly more stylish and luxe than others, which is why it ranks behind the guesthouse.) Other perks include a lounge with free afternoon tea and cakes, and free breakfast and Wi-Fi are also included in the rates.

A quirky retreat in the heart of Vienna, the Hollman offers bright, airy rooms for those more interested in a relaxing, versus over-the-top, vibe. Unlike the other properties on this list, there's no on-site restaurant (although an affiliated one is just around the corner), but it does have a spa with a treadmill, a small movie theater, and tons of freebies like breakfast, afternoon snacks, and daily fruit plates delivered to the rooms. 

Rooms do show slight wear and tear here, which is why it comes in at the final spot -- but nonetheless, the upscale Hotel am Konzerthaus is a solid boutique option, and still one of the best in a city filled with them. Stylish rooms feature custom artwork, and a lovely restaurant and bar include outdoor seating.