Most well-informed EvE players are familiar with the MWD-Cloak to warp trick. It is used to avoid being tackled by a hostile as you enter a system. The crux of the trick is you enter system, align to your warp destination, cloak (must be t2 cloak), and activate the MWD. At the end of the MWD cycle, you decloak and spam warp. When performed properly, it is very difficult to catch you, as you can cloak before they target you, and you enter warp before they can target you.
With the release of MJD's, this trick got a new module to help with nullsec travel. Employing a similar tactic as above, the MJD provided two major benefits over the MWD.
1.) You never had to decloak. The MJD would auto-decloak you at the end of its cycle, shoot you forward 100 km's while maintaining alignment, and allow you then instantly warp to your destination. Decloaking too early or too late is one of the most common ways to lose your ship when attempting the MWD-cloak trick, so not having to worry about this timing is a pretty major boon.
2.) The MJD was bubble proof. Bubbles don't prevent the MJD from shooting your ship forward 100 km's, thereby allowing you to zoom out of hictor and dictor bubbles, which are generally responsible for the death of most MWD-cloak travel in nullsec.
What is the stealth change? MJD's now decloak you when activated, and prevent you from re-cloaking. Since I've personally recommended the MJD-cloak trick to nullsec battleship pilots, I figured its appropriate to announce this technique no longer works.
That is all.