Which app is best to buy USDT?

Could you possibly enlighten me on which application offers the most optimal experience for purchasing USDT? With the plethora of options available, I'm rather perplexed as to which one truly stands out in terms of security, ease of use, and cost-effectiveness. Do you have any recommendations based on your expertise in the cryptocurrency and finance realm? Would it be advisable to consider factors like transaction fees, customer support, and the app's overall reputation? I'd greatly appreciate your insights on this matter.