If I could do it again (I have a 2" RC lift with Bilstein Shocks, which yields about 2.5 Inch lift at best), I would go with OME lift all round HD (or the OME Springs coupled with longer Bilstein shocks). There are benefits (and draw backs) of lift through 'suspension spacers', If you have the cash to spend go with lift through bigger springs and shocks - OME seems to be a good option. This setup is also very good for wheeling. If you want just large then go SL as mentioned above. I guess it all depends on the purpose.
Regarding angles, I would not want to go above 3" of lift without changing other components - CV joint angles and others would eventually cause issues down the line.
Another thing to look out for is the effects lift has on the ESC, at 2" lift I get a few 'issues' when doing a u-turn (you have to take it slower as this kicks in), for 4" and greater lift you will definitely get this exaggerated - hence the need for an ESC tweak.
Lift = bigger tires
this also will require programming the ECU. I don't know your rig but if you have stock wheels/tires then putting in bigger tires also has requirements (clearance from pinch weld, UCA bolt etc), each of these needs addressing depending on the size of tire and offset of wheel you will use.
I am personally not a fan of wheel spacers - despite their popularity. I would only consider this for an off road rig.
You will definitely need to consider changes in your front UCA, the angles caused by the lift will eventually cause the OEM UCA ball joints to fail, or at minimum a clunk each time you go over a speed bump. A good solution is the JBA UCAs.
You will also need to install an adjustable rear track bar as the lift will put your rear axel off centre - you can get these from BWoody or Rustys.
Just FYI, the lift is not just the lift, its all the other things that also need to be adjusted (if done properly
) . Its trial and error and relying on plenty of info the guys have done here with lifted jeeps, I am all for it, but worth mentioning the considerations
Best of luck!