Weight and exact dimensions are irrelevant for home use. Unless you plan to carry the device in a shirt pocket, the difference between 50g and 70g won't be noticeable. Also ignore 'preheat function' if you're not vaping in cold rooms, and don't worry about charging time—most devices charge in under two hours.

One thing you should not ignore is the warranty. A vaporizer is a small electronic device, and things can go wrong. A 1-year warranty is a sign of confidence; a 30-day warranty is a red flag.