Generally Press Releases (at the time I'm writing this post) are seeing a short term stick for reputation management purposes. However they are carrying some nice weight for building domain authority and trust. The most important thing is do not do anything unnatural with your anchor text as it will overoptimize your website pretty quickly. I'd recommend linking out with a reference to your Brand or URL and then maybe a FB/Twitter account.
As far as traffic goes, if you don't have anything noteworthy to say then it's going to be somewhat of a waste as it is not going to get syndicated as well.
Most free PR services are low quality and spammed pretty heavily by SEOs. A paid service is generally going to give you better results, but don't be fooled as many services will get you the same distribution but the price they charge will vary dramatically.