Depending on your needs and your plans for growth you may be able to get by with WordPress...at least for a little while.
If you're serious and are looking for something with more pay site specific features your best bet is to look at a system like ours that was developed specifically for adult. The main difference is that aside from just being able to build a site you'll get things like automatic video conversion/encoding to Web and mobile formats, mobile and iPad compatibility, VOD, tour and trial area management and other things you'll want for a serious pay site business.
My only advice is do your homework. There are a lot of people in this space marketing crap scripts and products that haven't been updated in 3-5 years. Make sure whatever you get has a long track record in the important areas and is giving you the best possible product and support. Otherwise it will just set you back and cost you more time and money.
If you have questions or want a live walkthrough of what
Elevated X offers feel free to email, ICQ or give me a call anytime 800-690-9277 ext 1
Good luck with your venture!!
AJ