Seems to be the luck of the draw. I've eFiled my last 2 EADs and never had any problems. In fact, the last one was approved in 2 business days. (yes, that's not a typo).
On the flip side, I've read posts from people who have had many problems eFiling. I've also probably read just as many posts of paper filers having problems. So in my opinion, neither one is better than the other.
The only advantage I see to eFiling is that your receipt date is the day that you eFile your EAD. When you paper file, you lose the time spent in the mail, and the wait on someone opening that mail. This is probably just a week or so, but that can make a big difference if you're close to 90 days before your current EAD expires. (so that you can apply for an interim EAD if you're processing goes over 90 days). Plus when you eFile, the USCIS takes your photos, so you won't have any worries of them sending back the pictures because they weren't taken correctly.
Anyway, I think you have to bear in mind that the people on this, and other boards, represent only a fraction of the people who are actually in the GC process. Also, most people only post when something "bad" happens. (Except for approvals). So sometimes, things may seem a lot more horrific than they are. (Hopefully people understood what I meant there and I don't start getting slammed..

)
To sum it up, "it's six in one, half dozen in the other", as the saying goes....
Regards and best of luck
Rav
*************************************
I485 RD 08/27/2002 (EB3/Canada)