I feed entirely pellets (except for nesting or travelling rabbits, they get hay). Decades of research (purina started making rabbit pellets in 1930) has gone into making pellets a complete and balanced diet for my rabbits - however a lot of pellets sold are more sold on 'what consumers will buy' rather than 'what makes a good feed'. (Researching the mills, working together with other breeders so one can become a feed dealer for the brand you want might be what you have to do to get good feed in your areas. What I want to feed is only sold in california sadly). Oxbow and Kaytee aren't good brands for feeding a pellet based diet; oxbow is okay as a supplement to other things imo but I wouldn't feed kaytee. Not only are they not super nutritional, they're way expensive. You can get a 10 lb bag of oxbox for the same price as a 50 lb bag of something else.
When you're looking at a pellet brand the key information is in the guaranteed analysis and the ingredients. You want timothy or alfalfa as the main ingredient -- and other ingredients that are exact in what they are. Some brands of feed change their formula with the season to keep prices down, so you want to try to avoid that. Looking at the analysis- without getting into to much detail, the most important part is protein imo. You want 15-16% for retired or non-breeding rabbits, and 16-18% for nursing or growing rabbits. (Oxbow is 14%, Kaytee is 12%. Purina complete, what I feed now, has 16% protein). Take a picture of the feed tag and post it here and we can give recommendations.