I've used EMG J pickups in a number of basses over the years ranging from Fender Jazz, to Spectors, to Warwicks.
I find them very consistent in tone. They give you a great, balanced tone that is deep, has plenty of punch and a crisp high-end. Don't let people's descriptions of these pickups as being 'cold', or 'sterile', put you off. I believe they actually allow the true tone of your instrument to come through and people are just not used to hearing this with most of the standard passive pickups that are more commonly used. In my view all you actually need with these is a passive tone control, so that you can roll off highs for a more vintage sound, when required. The flat open tone straight out of the box is just great. Powerful, punchy, articulate and no noise, or hum in any pickup blend setting. Completely cure the traditional single coil hum problem. I find them great for recording in a digital environment, where computer equipment can cause noise in more traditional passive single-coil pickups.
The quick-connect solderless EMG system is great and make installing these a doddle. All the components are high quality too.
Highly recommended!