Like a few of the recent toy lines, I have essentially every US released toy. From Armada onward, that's how it's been.
Alternators are included in this. I have every release thus far. I went so far as to get Rodimus from the KP line.
Now, there is the SDCC Hot Rod. I'm cool with it. I'm glad people can get him (kind of get him...), but that's not my issue. See, I'm tempted to buy this Alt as well, though I have almost no need at all for it.
Difference wise, there are some changed paint apps and fewer accessories. However, I'm still tempted to get this version, simply because it's out there. The completist thing compels me.

I know, that I am not the only one out there who goes through this kind of thing.
At what point do you, or have you, drawn the line and said, “Nope. I am not going to buy just for the sake of NOT ‘missing out’?
This doesn't have to just apply to those who spend lots on their TFs. It can apply to everyone really, it just depends on how and what you buy.