From my limited experience
costco shovels - broke both on their respective first outings, friends costco shovels all broke as well, they can't stand any levering.
Black diamond lynx - ok; eat your spinach, and act like Popeye!
Black diamond deploy - better than lynx, if you haven't tried anything else you'll be happy.
Orthovox beast 2.0 - beat the others hands down! Good blade edge for chopping through hard layers. Lynx severely struggles, deploy manages but is hard work.
Probe - as mentioned before very useful to ensure enough depth and no boulders in your snow bank.
Alpkit snow saw - useful when snow is amenable to cutting blocks
Other useful tricks - put some SOLAS tape on your walking poles (if you use them), great for marking your entrance, so you can refind your hole in the dark if you go for a wander, or out for a pee, and to hopefully stop other party members walking over the top of your hole. If planning an extensive excursion away from your hole consider also marking with a chemical light stick.
If near a buried stream coarse, probe to see if there is running water, and then dig it out as a water source to save time consuming snow melting.
If significant snow-fall and/or snow redistribution expected overnight which may start to accumulate over your hole, set a watch rota / alarm through the night and check your entrance isn't drifting in and you have a good air supply
Post edited at 11:51