It depends on your goals and circumstances. If you want to mine a specific cryptocurrency that has a stable and profitable algorithm, and you have enough money to invest in an ASIC and pay for the electricity costs, then an ASIC might be a good choice for you. However, if you want to mine different cryptocurrencies or have more flexibility and adaptability in your mining operation, and you have a lower budget or cheaper electricity costs, then a GPU mining rig might be a better option for you.