Very nice guesthouse in Vilnius. We've (family with 1 baby) stayed there for 3 days. I can recommend this hotel for couples and solo travelers and for families with elder kids (from 3-4 yo). The hotel located in old house without lift, so be aware if you are travelling with a baby.
For us it was an issue. But for the rest, hotel have very nice host, who will help you with everything you need. Breakfast is small, but very nice and served in the room. I like the decoration of the room (we've stayed in apartments on the 3rd floor), the room was very spacious and clean. The only thing i can recommend to the management is to add microwave oven and baby crib to the apartments, the rest was absolutely nice.

We stayed 2 nights at the Old Market Guesthouse after looking for a nice, boutique-esque and affordable place in our first trip to Lithuania, and it was lovely! The place was cosy and tastefully designed. We stayed in a room with squirrel-themed stencils across the wall, and somehow it worked :) And it had a big window facing the fresh food market opposite the guesthouse. Breakfast was excellent, and served in the room daily: fresh rolls, fruits and juice, cheese & egg and really good coffee just the way you like it. Yum. Staff was friendly and helpful, and helped us figure out our day trip to Siauliai, and booking us a taxi for some crazy hour in the night. Oh, and free wifi :)

Location-wise, it's quite close to Vilnius old town. And if you're too tired to walk, there's a taxi stand right across the street which is always ready with at least a couple of yellow taxis. There's also a small supermarket less than 5 mins away in case you want to stock up on necessities or snacks. That is if the fresh food market is already shut - really lovely to just have a wander in there anyway when it's open.

We loved it so much and felt so comfortable there that we came back and stayed another night after our break to Moleitai, en route to Poland.

The only possible con is that the room is a bit on the small side, and there's no wardrobe or cabinet for your clothes or bags (we put ours under the big table next to the bed), so probably wont work for long stay. But for a few days or nights, it's pretty much ideal! Oh, and you'll have to take some steps to get in, so not for those with difficulty climbing.

We stayed there for 3 nights. It was a two bedroom apartment room.
The good: Location. In the old town. Close to shops and restaurants.
- Extra towels and toilet papers were provided upon request.
The bad: - Lights on the hallway to the room were supposed to be on automatically by the motion censor but it was very slow and we had to walk up few steps in the dark. It was dangerous as we could not see the stairs and the ceiling was low for guys. Our room was on the third floor.
- Very squeaky wooden floor and it was cracked in one place.
- Not enough chairs. We were 4 people and a baby and there was 3 chairs in the room. So we have asked the staff to provide us another chair but it was not provided and there was no response to the request.
- There was no bedside table or lamps in the bedrooms.

Advantages:
- the service was rather good, the staff is friendly and helpful: at our request, we were given a kettle. They also helped us to plan our visit to Vilnius: provided us with the train timetable, consulted on the places to have dinner in town
- original rooms design: we were quite surprised to see a blackboard for putting down the time, when we would like to have breakfast
- the breakfast itself was included into the room price and was to our surprise very rich. It consisted of cornflakes, juice, coffee/tea, chocolate, cheese, ham, tomatoes/cucumbers and bread,
- central location
- free wi-fi in the room

Disadvantages:
- The audibility is rather high: we could hear the noises in the corridor and from the street
- The surroundings of the hotel is unfavourable, maybe, because of the close proximity to the Central Market
- Several ill-considered interior details: lack of hooks and shelves in the bathroom, chest instead of the wardrobe in the room, unsteady table.

To sum it up, I would recommend the Guesthouse to young people as it provides unusual experience for reasonable money.