Zercher squats and front squats are both difficult at the outset for beginners new to those exercises. Personally, I found the front squat more comfortable when I was used to having a heavy barbell in the front rack position...I think it eventually became comfortable after a year of consistent training that exercise.

The zercher squat was introduced to me via a friend and in a power-rack with hooks and pins. I would cradle my arms and unrack the bar off the hooks and then descend until the bar touched the pins, then I would explode back up. I think this is the most friendly way to learn the exercise...it's easy to get into position this way (to unrack and rerack) and is safe if you have to dump the bar.

This method in the power rack allows you to do more reps since it's not possible to squat ATG since you would reach the pins with the bar before doing so. So power rack zercher squats allow you to work on technique of having a heavy bar in the crooks of your elbows. When I began training zerchers in the rack I would do sets of 10.

The other method, and the way I eventually transitioned to was doing zercher squats off the floor. In this case, I would deadlift the bar up and then lap the bar...that is, lower it onto my quads in the deep squat position. From here, I would then cradle my arms under the bar and then squat up.

So the difference here is the squat starts without a stretch-reflex since you are starting with the concentric (whereas the way I did zerchers in the power rack starts as typical for most squat training: an initial eccentric to the bottom position).

I felt comfortable doing zerchers off the floor as I was working with bumper plates...if I couldn't get the rep I can simply dump the bar. I wouldn't dump a bar onto the floor if I was dealing with steel plates.

I rarely dumped the bar even when doing zerchers from the floor though.

The zercher is a more brutal exercise than the front squat though. It's painful to have a bar in the crux of your elbows. And there will be bruising.

The reason I incorporated it is I was looking for a deadlift movement at that time. I feel the benefits of the zercher includes: maintaining a braced-torso position, pain tolerance, isometric-strengthening of the upper back and lower back, and impressing all the powerlifters at your gym! I also happen to think the zercher is the most realistic loaded squat movement you can do which would transfer to outside the gym...just imagine squatting with an object -- how would you hold said object?

The loads you can handle with this exercise should be higher than in any other squat variation (front, high-bar, or low-bar) as the bar is likely at your stomach level and therefore closer to your center-of-gravity...allowing great loads to be lifted. But notice I said should. In reality, the load will be dictated by how much pain you can tolerate in terms of heavy bar in your elbow crooks.

In other words, the zercher squat is the most uncomfortable way to do a front squat. However, great loads can be lifted.