I have tried the aftermarket EFI kits (Edelbrock E-street, Fi-tech and Sniper 1) and honestly prefer my carbs over all of those. In 50 years of driving with carbs, never has a carburetor left me completely stranded. Not to say I never had issues (running rich, lean, crappy etc.) but the carb always got me home.
That's why my aftermarket throttle bodies sit on my shelf of shame and my small Holly sits on my 302 currently.
The aftermarket throttle bodies have their issues. Tons of threads just on this site on all of the brands!
They work great for some, not so great for others. Support??? Well some have had great experiences and some have not.
The Pro-Flow 4 looks interesting and haven't heard too many bad things. Cost would be a factor for me though but I'm old school. This is my hobby and my carb runs just fine
If I were to go EFI, it would be original stock explorer setup. It's the most work but the only one I've seen that no one has really complained about.
Whatever you decide, the folks on this site will help you get through any problems you may have!
Well that's my 2 cents (and it's worth exactly that)