They are just a bunch of independent realtors. It depends on who you get.
I had them help me fill a 4-plex. They brought in 2 tenants. One got laid off ~9 months after he started, they were great tenants, but ended the lease early. the other set was a bunch of college potheads. They got evicted after ~4 months.
The replacement tenant did not last either.
If you know what you are doing, it works. if not, learn. Use them for grunt work, not expertise. Contact me on my blog if you need help.