We stayed about 2 blocks from this Spar market and used it frequently in the latter half of our…read moretrip. We visited ~ 3 others as well while we were wandering around Vienna, so we got a decent feel for them. We used these to mostly to buy breakfast items for the next morning, and saved an appreciable amount versus dining out for breakfast. So I was grateful to have access to a Spar nearby.
There are quite a number of Spar markets near the center of Vienna. You will encounter them every 6 - 7 blocks, it seemed. The concept is that they squeeze as much of a regular supermarket as they can into relatively small spaces. There did not seem to be a standard layout, so each varied somewhat. The aisles snake around whatever area they have, and are narrow. Given the reduced shelf space, they may need to restock shelves during the day (versus after hours), which can lead to extra congestion.
Spar offers small baskets which you can use to hold your items before purchasing. They do not have shopping carts, as there would be no room for them in the store. While I would not describe shopping at Spar (especially in the evening) as a pleasurable experience, I doubt that I could design a better market given the space constraints. It serves its function.
My description above is not meant as a criticism. Spar is trying to make the grocery store concept fit into the space model they have. This requires some compromises. It isn't that they are doing anything 'wrong', just that there may not be a better way to handle this.
Note that each store seems to have its own hours, which may not correspond to the next closest store... If you can go earlier in the day (at least not within 2 hours of closing time), crowding seemed to be lessened. Also, they tend to close off some shelves (with curtains) and dismantle things like their large fruit-juicing machines an hour or so before they close, so that is another reason to go earlier.
Lines can snake back from the check-out stations quite a ways. As you get closer to check-out, they may have someone directing you to an open register (or they may not). If you want a bag to carry home your purchases, they sell those near the check-out (for a nominal charge). Or you can bring your own.
One Spar we visited seemed to have fruit flies on the pastries in the evening, but it was not this one. After that, we were extra vigilant in inspecting the fresh bread. We never saw them elsewhere.
After the trip, I do have a fresh, unexpected appreciation for the local, less space-constrained grocery stores back home.