If you don't want to spend a lot of time rigging, you can always take an existing rig and just replace the artwork.
The most time consuming part of rigging is probably setting up the Smart Bone Actions. Smart Bone Actions often requires setups that are specific to a character, so using an auto-rigger probably won't help much here. But it's possible to make a great character rig without using any Smart Bones at all. It really depends on your character designs and the style of animation you're going for. At my workplace, I tend to use a lot of Smart Bones in my rigs, but I've also built rigs there that hardly use any Smart Bones.
The second most time consuming part is drawing the character art in Moho, especially if you want vector art that deforms nicely. But if you can't draw in Moho, you can always use photos or hack up some vintage clip art and apply mesh warps to those items. Heck, if you're going for the paper cutout look, you don't even need mesh warps...just Layer Bind the parts directly to the bones. The only limitation is the artist's own creativity.
IMO, the LEAST time consuming part is building the skeleton. Building a basic skeleton in Moho shouldn't take more than a few minutes really. It's just click and drag with the Add Bone, and copy/flip any symmetrical limbs. Of course you need to know where to click and drag and how many bones to create, but that skill comes after a little practice.
For example, here's a basic setup I like use...
I just timed myself in making this skeleton and it took me exactly 3:19 min to create this. And I haven't had my morning coffee yet. If this process took me a lot longer, and I was going to be really smart about it, I'd turn this into a template project and just keep reusing the that for each new character.
The skeleton for a basic face setup isn't much more complicated. I usually have a single face 'mover' bone parented to the head bone, and then all the other face bones (EyeL, EyeR, IrisL, IrisR, EyebrowL, EyeBrowR, Nose, and Mouth,) are parented to that bone. Oh, can't forget the ears...add two more bones, EarL and EarR, to the head bone. Again, this takes only a couple of minutes to create. Like so...
Binding might seem the most mysterious part of rigging since there are so many ways to bind artwork in Moho. If you're a beginner, keep it simple: break your character art down into layered segments and just Layer Bind them to each bone. If you want to go more advanced, you can use Selective Flexibinding, in which case you just select the artwork layers and the bones you want to bind them to, and choose Use Selected Bones for Flexibinding. If you're using vector art, another good option is Point Binding...it's not as 'organic' as Flexibinding but it's very predictable.
A lot of body parts can rely on Switch Layers, and these layers don't really need any rigging at all. Just fill up the Switch Layer with your drawings, and then Layer Bind the Switch Layer to its bone. (i.e., the 'Mouth' Switch Layer to the Mouth bone, 'HandR' Switch to the HandR bone, etc.) You don't need a fancy Smart Bone setup to switch drawings, just use the Switch Selection window.
Of course where gets complicated is in specific character details: Does the character have long hair? A tail? Wings? Are the legs digitigrade, plantigrade, or unguligrade? Does it have jointed or noodle limbs? (With Vitruvian Bones, the character can have both!) How complicated is the clothing? Does it have a lot of flappy and flowing bits? But even here, you can simplify things to use minimal controls, and still have something that looks good. It all depends on your designs and how you intend to animate them.
IMO, an autorigger is only useful if you're willing to restrict yourself to exactly what the autorigger produces. There's nothing wrong with that, especially if you plan you're production around that idea. But one of the most appealing features of Moho is its flexibility, and by relying on an autorigger you may be losing a lot of that flexibility.
I think once you've built a few characters with Moho and get an understanding of which approaches work well and which don't, you really don't need an autorigger to work quickly and predictably. Like anything worth doing, it just takes practice.
My advice to a new Moho user is to keep your rigs simple and actually
complete a few projects using the simple rigs. This makes it easier to figure out your personal workflow for getting an animation finished from beginning to end. Once you get the hang of it using simple rigs, then try applying more advanced techniques in your next project. I think you'll find this approach very fulfilling.
Hope this helps.