Funny that when I tried the Synapse based driver it demanded a user ID/password pair before it would let me continue. There was nothing optional about it.
To clarify/add what the previous person posted, Synapse is both the driver and the cloud storage software. The username/password is required to be able to use the software. This allows the software to store the user settings in the cloud. I can understand already why some may take issue with it. With that said, if you are playing offline or have no access to the internet for extended periods of time, Synapse won't prevent you from using your mouse or mouse settings, but you won't be able to save any changes to those settings either.
Like I said in an earlier post, I like the idea of Synapse, but the current version is just not ready for prime time yet. It's also unfortunate that the newer Razer mice do not have another driver option other than Synapse (not counting 3rd party software). I would really like to see improvements to Synapse, but even more so I would like to see standard drivers so users can choose not to use Synapse.
If I were to rank mice companies based on Mac support, this is how I would rank them right now.
1. Razer - Only the Ouroboros, Taipan, 2012 Naga (Not the Naga Epic), 2013 DeathAdder, and 2013 Orochi require Synapse. There are still 8 other mice that Razer are still actively selling that do not require it. Not to count the numerous other mice that are still available through other sites.
2. Steelseries - Most if not all of the mice now have Mac support, but they only have 1 or 2 wireless mice and both are WoW branded.
3. Madcatz - I put Madcatz above Logitech right now because their "gaming" mice have Mac support where Logitech gaming mice do not.
4. Logitech - Only their non-gaming line provides any type of Mac software support. There are ways to get the features of some of their gaming mice to work on Macs, but until they support Macs natively, I won't be wasting my time with them.
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The choice was install the Synapse based driver or find the older driver for the device. Eventually the older driver will break with OS upgrades.
Why should I need cloud storage for a keyboard or mouse attached to one computer? It's an extra dependency that seems like a waste to me.
I think the key word is "need"... You definitely don't need it, but I think they were aiming for the LAN gaming crowd. I can see the benefits of being able to use your mouse profile on any computer since the settings are saved in the cloud, but it's not something most people will "need". I hope Razer changes this in the future and makes it an option instead of a requirement.