I will give you my thoughts based on my experience:
Front end parts wear out faster the higher your lift the front end. Even with UCAs, you can get a better tire alignment at the upper ball joints, but the tie rod ends will be a steep angle, creating more vertical forces in the center link, and your idler arm. The more you lift, the steeper the angle of the lower control arms is, which can also bind up and interfere with your lower shock mount and CV axle boot. Of course, I did wear these parts by off roading harder than you intend on using your X for...
This is just to serve as a reminder...UCAs do not fix all issues related to the lift. You can mitigate a lot with heavy duty parts, but you can't change the geometry that much with absolutely no increased wear and tear. You may not see the wear as fast as I did, based on how you drive, though.
Aftermarket UCAs are designed for one purpose: Lift your vehicle and align the upper ball joint. If you aren't into offroading, I don't see it as being worth the investment, especially given the other potential wear factors to the other parts. If you just do a PML, I would not worry too much on wearing out the front end parts. In my experience, I would worry more about wearing them out with UCAs and a higher lift.
If you are just going for a hunting truck to get through some trails, and aren't into towing, I would recommend:
1) Put the PML shackles on the rear, and leave the rear alone
2) Adjust the front torsion bars to the correct bump stop gap and keep the stock UCAs. Note that with the PML, you are usually limited with how much lift you can get. You will probably have a nose down rake slightly. That is normal.
3) If for some reason your upper ball joints really need to be replaced, or you absolutely hate the nose down rake, I would then make the jump to UCAs. You can get more lift and wheel travel. The upper ball joints are now serviceable with 4 bolts, and the UCAs are very strong. You can also get a perfectly leveled "PML" if you want...You won't need to use all of the adjustment in the front, but you have that option if you want to lift even more...
4) If you really like lifting your vehicle, and want to get more, buy the "Adjustable shackle" from 4x4parts.com ($90), and install that at the tallest setting and replace the PML shackle. That will bump the rear end up another 3/4", and you can then lift the front end a bit more with the extra room from UCAs.
Additional upgrades I would recommend:
1) Heavy duty tie rod adjusters
2) Total Chaos Idler Arm brace (best design over 4x4parts and Calimini)
3) Bandit4x4 idler arm bushings
4) Bilstein shocks
Note: I don't like stiffer springs...so I won't recommend adding leaf springs to the rear or stiffer torsion bars to the front. That is just me. I don't like the harsher ride unless I am towing a LOT.
This is my advice based on how I built my truck...
In hindsight, I reached the conclusion that the UCAs helped the alignment of the upper ball joint, they are stronger than stock, they allow more wheel travel/lift...BUT, in my opinion, they allow you to physically lift the front end near the geometric limits of the rest of the front suspension and steering (recreational hazard of offroading...). You will wear parts less with a PML than with the 3" SL...simply because the geometry is changed less.
If you aren't in desperate need of a higher than PML lift, and if you aren't really offroading a whole lot, I think UCAs and revolver shackles and add a leaf packs just aren't worth the time, effort, or cash.
. If you do get UCAs, you can use the adjustable shackle, add a leafs, revolver shackles, etc .... you have a lot of choices for the rear.
