I worked at a company that used Perforce. It took 2 weeks to get a branch created. No thank you.
"Branches", the way we use them in git are more like perforce Shelved CLs.
Fwiw the only major issue I've had with branching is the fact its a full fat copy of your source which can end up taking up a load of space depending on how large your application is post build and how many binaries you dump into perforce.
They seem to be pushing towards "streams" now, but I've heard they make it easier to create development branches but haven't worked with them to find out.
p4 branch <name>
(fill out the mapping)
p4 integrate -b branch //...