What type of riding do you mostly do? What is the weather like where you live?
The reason I ask is that there are some differences in the vests offered on the market. Some are approved by a couple of testing agencies, and some are not. If you are jumping a lot and plan on eventing, I would recommend an approved vest. The trouble with them is that they are mostly less comfortable than the unapproved Tipperary-type vests. If you live in a hot and humid environment, where that weather is likely to make you decide to not wear the vest, I would say get the cooler, more comfortable (and more expensive) Tipperary or one of their knockoff copies.
While the approved vests are more protective and a better choice for showing and jumping, I would rather see you get a lessor vest, than none at all.
I still use my Tipperary vest and accept it is less protective.