I'm running Sierra and there are differences from Mavericks, but in general, I have no problem with the OS.
To check the model number hold down the option/alt key, go to the Apple menu and select System Information.
macOS 10.12 (Sierra) requires one of the following Macs:
iMac (Late 2009 or later) Model 10.1 and higher
As well as:
Mac OS X version 10.7.5 or later
2GB of RAM (4GB minimum is more realistic)
9GB of free disk space
How to get macOS Sierra
One option is to create a new partition (~30- 50 GB), install the new OS, and ‘test drive’ it. If you like/don’t like it it, you can then remove the partition. Do a backup before you do anything. By doing this, if you don’t like it you won’t have to go though the revert process.
Check to make sure your applications are compatible.
Application Compatibility
Applications Compatibility (2)
El Capitan 10.11 Compatibility information
macOS Sierra 10.12: Compatible Apps
Also check to make sure there is a compatible driver for your printer.
Open Disk Utility, select your hard drive (step 1), then the Partition tab (step 2), and select the partition. Using the /// at the bottom move it up (step 3) until the size box decrease by about 50 GB. Select the newly created space and hit the + button (step 4). Name it something and select Mac OS Extended (Journaled) as the format (step 5). Then hit the Apply button(step 6). Download the installer from the App Store and when it starts, point it at the new partition. You might want to make a copy of the installer outside the Applications folder to avoid having to re-download it in the future. Once installed, restart with the option/alt key held down, select the new partition and reboot. Test away.
