I have both of them. After a Calatrava, which is nice but in another league entirely, they were the first two fine watches that I owned. My Lange 1 was the classic: silver face, yellow gold case, blued hands. I just thought that this was a timeless design and any serious collector had to own one. I've never regretted it; it is a solid, heavy piece, and I never tire of it and come back to it often; in fact I'm wearing it right now. It has a heft and Germanic solidity and precision to it, in both look and feel, that FPJ does not have. Unsurprisingly, FPJ is more French than German -- more delicate, more lyrical, more playful than Lange & Sohne could ever know how to be. Feeling the sensation as you wind each of these two watches tells you all you need to know about the differences. My first Journe was an Octa Lune in red/red, before the switch to red gold movements. It is stunning as well but, as I indicate above, in a different way than the Lange.
Subsequently I have picked up some other watches; I'm very picky and only collect pieces that achieve my own personal idea of aesthetic perfection. I don't like overly complicated faces and go for a classic look. The subsequent watches have included a Chronometre Souverain in red gold (the first one in the US and drop-dead gorgeous!!!), Gerd Lang's Chronoswiss quarter repeater in steel with a white face, and another very Germanic watch, Marcus Lang's King Johann in pink gold.
So bottom line is that you should pick one at random and before long, you'll end up with the other one as well!