I've had an ET-732 for a couple years with no issues still using with the original probes.
Care when using, cleaning, and storage do make a great difference in the life of the unit.
I like the ET-733 because the display is slightly larger and gives you added information like high and low settings, and it has customizable presets for your meats.
Although I use a BBQ Guru, it is nice to get an alarm, or just to glance from the recliner to view status of the cooker and the meat without loading an app on my smartphone.
After many years of watching a pit, going out every hour or so to see how things are going. These were great times when I was younger and I actually enjoyed it.
Now that age has seemed to win the battle with me, I enjoy the new armchair / couch potato approach to BBQ Smoking. It is great to get much more sleep and have some peace of mind without having to go up and down the steps to check things out.
Humphrey's DownEast Beast W/BBQ Guru