Well, if you don't go off road...and its just to fit 35', do a 2" BL and you will have no worries.
A BL is to fit larger tires.
A suspension lift is to raise the frame.
The suspension lifts can be confusing, but, just try to remember that they all do the same thing...they make the distance between the drivetrain and frame longer.
It doesn't matter what brand, style, etc...that's what they do.
If one includes a part the others don't, like a longer or adjustable track bar...it doesn't mean only that kit NEEDS one, it means that that kit COMPENSATES for the axle shift that ALL lifts MUST produce....and the other's do not.
If its an OPINION by one maker that you need that compensation, vs not needing it...that doesn't change the physics.
(Needing can be subjective...axle shift is not subjective, how far is TOO far IS subjective)
So - ALL lifts that lift you 2.5" will shift the axle by the EXACT SAME AMOUNT, etc.
If one kit compensates by using a new bracket, or a new bar, etc...then you can compare which solution might be better/the best value, or whatever your priorities are.
If you want more wheel travel, and better handling, to compensate for the taller center of gravity you get with a lift, then, new, longer and properly valved shocks will be better than a shock extension....and a shock extension will be better than leaving the stock shocks as is, etc.
A coil spacer gives the same lift as a longer coil...but might not compress as short, and might not have the best spring rate considering the potentially new shocks and their valving, the new, heavier tires and their weight, and the higher center of gravity, etc.
And so forth.
The suspension lift only increases the ride height...so, on road, and under most conditions, the tires clear....but under compression, they can hit what ever they would have w/o a lift.
The Body Lift just raises the body, so the COG stays about stock, and the tires have the same clearance as with an equivalent SL, except that that clearance doesn't dissapear when you go over a bump.
Its also cheaper.
If off roading enough to matter...the SL gives room for a more flexible suspension and other advantages, like ground clearance.
Larger tires give ground clearance too though, and ONLY larger tires will pick up the ENTIRE truck, axles and all.
Food for thought.