I own the Utillian 721 and I love the convection heating as it gives me the ability to reheat my bowl and the cannabis bakes more evenly. The downside of that vaporizer has been the preset temperatures which doesn't give you much flexibility in controlling what cannabinoids you release. What I love about the 620 is you can use a precise temperature and there's a great range from 160 - 220C (320 - 428F).

It also has a smaller chamber which means using less cannabis at a time. This is a good vaporizer to take with you on a walk, a party or anywhere you need to be more discreet. I don't mind the smaller chamber as I save on cannabis using less at a time, and find I don't refill the bowl any more than I did with the 721. However I've found you can only reheat it once, any more than that and it tastes awful. There's a metal tool built into the device, this is meant for removing the vapor path for easy cleaning, however you can use it as a stir stick if needed. It's a good idea to stir up your cannabis before reheating a bowl as you'll get better flavour.

Cleaning this vaporizer is a snap and I don't find I have to do it quite as often as I do with the 721. The pieces come off easily, the cap is magnetic and is easy to clean. There's a small screen inside a rubber cap that can be a bit tricky to get in and out to clean but it's not too bad. I find just a q-tip with isopropyl is enough and I never use the brushes however the brushes made it easier to get the stick resin off.