I wouldn't say springs are easier to install than spacers. Springs require compressing the factory spring so you can take apart the strut assembly, then compress the new spring and re-assemble the strut. I just bought a really nice spring compressor that should be way better and safer than the little clamp things that you can rent at the auto parts store, but I'm still not looking forward to it. If you are just installing the spacers you can leave the struts intact which really saves you some time and headaches.
There are not many people documenting a 4" lift, but the few who have I've read the forum posts and watched the videos many times over. Usually its on a Renegade. Cherokee lifts might shed some light on issues also, but that platform is very different.
Problem 1: CAMBER. Installing either the 2" spring kit or the 2" spacer kit might not cause you or your shop too much work to get the camber adjustment correct. Putting both in for the 4" lift will make it harder to do for sure. Maybe not impossible, but some shops might get frustrated with the situation and quit trying.
Problem 2: TIRE SIZE. If you are thinking that all of the extra room will let you run larger tires, you are in for a lot more work. First, you can't really go that much bigger. The factory tires are about 28". I've got a tire/wheel combo that is just a hair over 30". If I can get the wheels to sit in the wheel wells, I'll have to convince the computer to adjust the speedometer via AlphaOBD software. This is when everything looks like it fits, but then the tire rubs when you turn the steering wheel. Maybe its all the time, or maybe its only at speed when going around a corner, but its probably because the tires are not only taller but wider also. I'm expecting to have to do a "pinch weld mod" and rip out the factory wheel well liners. I might also have to cut the lower corners of the front wheel well openings a little to allow the rubber to clear. If it looks too crazy, I'll abandon the situation and buy smaller tires.
I would never go to all of this trouble just for looks. I use my compass on muddy hills often, and the factory tires are the only limitation right now. They clog up with mud instantly when its too wet and they either spin or the traction control cuts power to the wheels. I've never run out of horsepower or torque yet, so even though I'll be gaining weight and losing torque with a 30" tire, I'm hoping that having 16" rims with TOYO AT 3 tires and airing down will more than make up for it. I also just purchased and set up a QUICKJACK hydraulic lift for this project. I'm probably going to wait another two months before even trying to do this.
If I had to do it over again, I think I'd just do no lift and get tires that fit on the factory rims. As it is, I've finally purchased everything and I'm going to give it a shot.