Once experienced there is no going back. Worth every cent. I am using an HMD for a year now and it is mindblowing each and every time.
The only thing i recommend is, to test all HMDs that are on your list as possible candidates. While some parameters are measurable (weight, pixels per inch, space for glasses etc.) there are some differences that fall into the categorie of personal preference.
Most shops will not use optimized settings though, so image sharpness, texture and shadow quality and frames per second may differ by a large degree in comparison to an optimized gaming rig with optimized graphic settings, so first impressions might be a bit underwhelming. Once you turn up the pixel per display settings things look a whole lot different.
If you decide to buy, be assured, that your monitor setup has seen its final days...