Had a confirmed reservation for rental from Covington Airport (Cincinnati). Upon arrival at counter, saw a non-moving line of about 20 people. When asked at desk about honoring our reservation, clerk responded, "Everyone in line has a confirmed reservation". After half an hour with no movement in line and no information from desk, we went to Hertz desk and paid about $300 more than the Budget price to get a car for the trip. A woman in line with us said she had been there to pick a car the day before and was told, "Come back tomorrow" -- it was now her tomorrow and there she was at the back of the line with us.
Recommendation: Clerk at the National counter told us it was not uncommon for Budget to have this problem since they "Managed their fleet very tightly". I would rent from a company that didn't follow that business plan.