The whole point of a modified rod such as Johnson's is that you drive in the "old" off road height equivalent at all times and at any speed, without assistance from the LR4 suspensions switch. You only use the switch to raise the car another couple of inches or so when you really need that extra lift - crossing a challenging rock garden, fording deep rivers, obstacles requiring the additional ground clearance you couldn't manually invoke before, etc. Then you go back down as quickly as it is safe to do so, You really shouldn't drive with Johnson Rods and off road height for long stretches. Whether on road or off, and besides putting quite a bit of undue stress on suspensions parts, you will have almost no upward suspensions travel and that will indeed result in a rough and jittery ride if you are lucky, and suspensions faults if you are not, as the sensors could easily hit the upper limit and decide something is not right.
As far as the ride in normal height + Johnson Rods being "great", well... I can simulate the rods with my LLAMS module and I don't think it is that great. It's fine in the city or on a highway at speed (as long as there are no strong crosswinds...), but handling on twisty roads suffers because your center of gravity moves up accordingly and gravity is, well, a *****. Car looks great lifted though, no questions about that.
