The best advice is to go and test ride a variety of brands. Geometry is different from brand to brand. Just because some else likes one bike doesn't mean that it will fit you. Once you test ride, you will know which brand fits you the best, then go shop for that brand. Buying used with better components is great provided it fits you well. There is nothing worse than a long ride on the wrong bike, but nothing better than bike that fits and miles of road in front of you.