I understand you're comfortable around a soldering iron, but as a general rule - complexity ranges from:

straightforward -
bolt on necks - marginally easier to play around with as you can undo the screws and add shims (not often required), etc.
solid / slab / chambered body with no binding / veneer - sanding is pretty straightforward and nothing to be ultra careful about.

slightly more care required -
binding (need to be careful with coarse grain sandpaper and stains)

more complex -
glue on necks - more fiddly at the end, once they're glued, more tricky to get apart - so you want to get it right first time
veneer tops - thin so need to be careful with sanding
some hollowbodies - getting the wiring in can be fiddly

That said - from a woodworking point of view - with care, I believe anyone can get a result that they will be content (if not happy) with. If you're not happy with it - often you can sand back and start again anyway... As with anything, you can trick things up and add complexity - burst finishes, changing the shape, adding / replacing binding, certain spray effects, etc. Up to the individual.

From a wiring point of view - it can be as complex as you want. In general the easiest kits are the ST, TL, PB, JB style, where most of the wiring is pre done - in essence there are 2-3 solders. If you're confident with soldering, you can always redo these kits with new pots and caps and in essence they're all about the same. More complex kits (e.g., double neck kits) tend to have a significant number of solders to get right, or are more tricky to wire up (hollowbody kits like the ES style - all access through the "f" hole). If you want to get funky, you can trick up the electronics to add effects, funky wiring, etc., up to you. If you're really uncomfortable soldering - there are even some options for after market plug in kits / solderless pickups and components.

Ultimately - the kits are as simple or as complex as you're comfortable with. Nothing from the Pitbull range is beyond an amateur who is willing to take their time and step through things carefully and ask questions when not certain how to proceed. I have seen some total rank amateurs get good if not awesome results out of their first hollowbody, or have had issues with their kits, etc., when they have been prepared to take their time.

Personally I started with very few tools, limited woodwork or wiring experience and have now scored myself a mod role for my sins... Go figure... I think if I can then anyone can... .