Start with how much counter you can give up, then decide on air frying.
Countertop footprint, clearance and usable capacity
The Mini, Compact Smart Oven and BOV680 suit small kitchens, and the BOV900 and BOV950 need a generous run of counter. Published dimensions vary, so measure your space and allow clearance on top of the body. The BOV680's manual asks for 4 inches on each side and 6 inches above, and you should read the manual for any other model before assuming the same numbers.
Usable capacity matters more than the pizza number. The BOV900 fits most 9 x 13 pans and a 12-cup muffin tray. The Mini and Compact Smart Oven are limited by chamber height and width.
Toasting, baking, standard convection and Super Convection
The Smart Oven Pro and Smart Oven use standard convection, which you switch on and off. The air-fry models use Super Convection, a stronger fan mode that crisps food. The Mini and Compact Smart Oven have no convection at all. None replaces a dedicated toaster, and toast can brown unevenly depending on load and rack position.
Air frying, Element iQ and connected features
Element iQ is Breville's way of directing heat where the food is. Air fry is the real divider: the BOV900, BOV860, BOV950 and BOV680 have it, and the others do not.
Connected features are narrow. Only the Joule has verified Autopilot and monitoring. Recipe access in the Breville+ app appears on unconnected models too, so recipe guidance does not mean connected control.
Included accessories, warranty and long-term value
The air-fry models carry a 2-year limited warranty, the others 1-year. Coverage applies to material or workmanship defects, and the remedy is decided under the terms, so it is not a service-life guarantee. Parts availability is not guaranteed.