What type of plugs do YOU use? Options

[ActionClaw]

When I was at the auto parts store today I noticed there was a sale on (both Platinum and Copper Classic) SplitFire Spark Plugs. It was a great price so I figured I might as well put in a new set. I told the salesman what I needed. When I did, another guy behind the counter overheard me tell him "'95 Celica" and kinda mumbled a warning "I wouldn't do it". I wasn't sure he was talking to me. I looked over, he stopped what he was doing and repeated "I wouldn't do it". I asked what he meant and got "I wouldn't put those plugs in a Celica. NGK." Someone else there agreed; NGK only.

I've see some others here use NGK, there's been talk about E3 Diamond Fires, etc. Sure, there are differences but I didn't think there was that much of a difference between one brand and another. Besides, I'd heard SplitFire's were supposed to be good plugs?

Anyone else here ever hear this (NGK only)?
Why would NGKs be so much better or more appropriate for use in a Celica?

Is this Toyota's recommendation or just opinion?