I am new to Revit MEP. I could either purchase live support or rely on this forum (or both).
How many of you have been able to get the help you needed from this forum to be able to get out of a jamb and get back to making progress on your projects?
As you can see from the lack of response to your post here, sometimes the responses from these (and other) forums can be unpredictable. Posts/Threads can be missed, may not be explained well enough, or perhaps no one knows - all of these can happen and you'll end up sitting and waiting for a response that may never come. But often, a well-composed question will get a response if anyone has one. The regulars are typically very willing to help, which is typically their motivation for being here.
In contrast, the purchased support will always be reliably available. If you choose to use the forums (which is recommended even if you purchase support), I would suggest perusing more than this forum alone. One such would be AUGI.com.
Support and subscription are highly recommended. As CADastrophe stated, the forums can provide help, (trying searching first). I have certainly found and received answers here. But there have been times where I needed help now so I could continue being productive. Being able to call your Reseller/Support is valuable.
With subscription you'll have access to all the upgrades and latest versions. Plus in the multiple versions of Revit world we live in, you'll be able to access multiple versions.