It depends on your preference. If you see yourself doing some mild welding in the future, then the DC unit is the option you should go for. However, if you intend to do heavy-duty works such as aluminum welding, buying a welder that works on both AC/ DC will come in handy. The price difference between both is nothing more than a few dollars. However, it might come in handy for those doing massive duty works. AC is ideal for high-end welding while DC for small DIY jobs.