I have an ACE suit and PRO briefs. I usually wear the ace with the straps down as a brief would be. The ACE stuff will stop you dead in the hole and give some “pop” out of the hole from all the stored up tension. The ACE works well with a med wide to real wide stance. Just literally keep sitting back and the suit will take care of you.
You may have to stretch the leg open with a football to dial in the fit as the leg opening are tight. This means that the brief will NOT slip up your thigh as other stuff might. ( I only have very minor slip up in my pro briefs in the winter, until I get a little sweat going on. Then they stick well. The ACE has a tighter “groove” than the Pro’s do. Probably won’t be a problem unless you are used to OLY type squats where you sit down more instead of back.
The Pro briefs are my “go-to” pair. I LOVE those. They do not hinder my squat form at all and have a wide groove that is very user friendly. The wider I stand, the better the briefs seem to work. They don’t have the stopping power of the ACE but they are very good and you would not be disappointed with them. Since this is your first pair of briefs, the PRO would be a great option. These are not “starter briefs” per se as they are serious shit man, but they are very easy to learn and will last you a LOOOONG time. I’ve had mine for about 3 years now and they feel pretty much like the first time I used them.
The Pro briefs are great when used under a suit. Until the Jack stuff came along, the PRO brief was under many a squat suit, including non metal suits…
I have no experience with the Jack line but from what I’ve read, it is like a mix between the ACE and Pro in terms of stopping power but “springy” in the hole like the pro stuff.
Hope this helps.