If you want an easy and robust deployment, you go with Ubuntu 14.04 and standard Intel/AMD-based hardware. There are many people out there that have that environment for Odoo (formerly OpenERP). A "regular" Debian installation does work, but you might have more work adding python-libraries and other software that Odoo need and fewer people to ask if there are problems. The difference is small, so if you like Debian better, go with Debian. With Ubuntu and Debian you can have the latest and greatest releases of Odoo.

Synology are an even narrower platform, that means that the community working with it are smaller. There are a risk that Odoo (OpenERP) are not the latest release over time, a risk that you don't have all libraries you need to do what you want etc. You cant add more RAM or CPU that you can do with a conventional server or a VPS. If you have the harware, finds joy in getting things to work and have much time, then go for Synology.

The fastest and cheepest way to get an instans running of Odoo are a free account at odoo.com (up to two users i think) or rent a VPS digitalocean.com, rackspace, glesys.se etc