I've been here once for lunch and once for late night snacks. Both times, the service was not particularly fast but some prompting got the attention of the staff. Their mixed appetizer plates are quite large in serving size and make for a great sharing dish, especially if it's not a full meal and just an extended snack. The lunch portions are quite reasonable and are usually just enough for one person. It does get pretty crowded at lunch, so make sure to call ahead of time to get a table. By contrast, it's not that difficult to get a table in the evening, even when most other places around there are closed and it's one of the few places still serving food.
There's nothing particularly remarkable about Gabby's, but it gives off a pub/bar atmosphere, just as one would expect. It's comfortable, there are no surprises, and it seems like the sort of place that you could rely on over time.