AIUI Fix-a-Flat is a get-you-home (or to a tyre shop) measure not a permanent fix. Most people avoid sealant in bike tubes, but some folk swear by it, particularly the Slime prefilled tubes. If a puncture is too big for sealant to close, the presence of sealant can make it impossible to apply a proper repair patch so that tube is trash. If you have a problem with punctures you might want to go tubeless - that seems to be the best use of tyre sealant on bikes. Most other puncture-resistant tyre solutions cost too much in terms of weight and ride quality for a typical cycling enthusiast to entertain their use.