Most make the 110 / 220 decision based upopn what they have available. The 'best' or most versatile set up for a new build is a large 220v, say 5500 or 4500 element controlled by a pid / ssr. With this the wattage is variable and can be dialed to what you want / need. Running a 2000w 110v element at 100% is very easy and effective to do on a 20amp gfi outlet, but it is really an easy (fast and dirty) alternative. Really depends on how sophisticated you want to go w/ the build, both in time and $$.