Virtual DJ
Virtual DJ is a freeware. It has everything you need to start, and perform. Many controllers can be used to perform, unfortunately most are un-native. Which means you have to modify all the settings to make it work for you. Also, it is a entry level program. You might be able to use this program as a expert, but your peers and customers will want you to be able to use something more “professional”. Virtual DJ does not get the respect it deserves for EVERYTHING it does, but will never meet a clients or tenured DJ’s expectations.
The entry level/beginners software.
Traktor
Traktor used to be the best “technical” favorite software. All of its features that it pioneered were taken and implemented to the competition, and at some point feel behind with popularity. Although its main user base has wondered on to other software, its ability to integrate to its parent developers’ (Native Instruments) programs, and its development of its own hardware towards the native equipment it uses make it surgical to use.
Highly respected and heavily modular. Just hard to master.
Serato
Many controllers are able to pick up and play this software out of the box. It simplifies the DJ vision onto an interface that spells out that vision, but unfortunately its overly simplistic interface hurts anyone in the entry level. It takes mild understanding to know how the interface works. Then a greater mind to become proficient to its implied simplicity. Not easy to use as a beginner but Serato is the most popular software.
The general club standard.
Rekordbox
Pioneer’s one stop shop. Designed mainly for Pioneer equipment. Has the ability to use a laptop for performance but also prepares tracks for Pioneer’s synonymous DDJ equipment with the use of only USB sticks. A lot of information at the start, but easy to use its custom settings to your own preference. All Pioneer controllers have a similar layout. The software is built in the same way to help you navigate the two seamlessly.
Professional, Elegant, Expensive. Pioneer.