Have heard people swear on using screws and some on nails.  Which do you prefer and why?

I'm an electrician so I would use screws. I suck at nailing.  

Buy deck screws with either a Torx or square head, not Phillips. Usually you get a free bit with the box of screws. Use nails and you'll be pounding them back down every time you're using the deck.

Yep, if you use nails, they will be popping back up constantly.  It will drive you mad having to pound them all back down again.

Screws, and don't cheap out.  Buy good, treated ones that won't rust out in three years.  You'll thank yourself later if you ever have to replace a deck board or access a buried line or something.

... and +1 on the square drive.  Much less finicky engagement between screw and bit than with a Philips.

Screws.

Nails are for shear applications, where the stress is perpendicular to the shank of the fastener.

Screws are made to hold to pieces of wood together in longitudinal applications, parallel to the shank.

Dad and I used nails when I was growing up.

Dad doesn't do anything right.

Good quality deck screws, as stated above.

Screws.  At a minimum, ring shank nails.

A good deck screw holds better...

Screws are best. I used stainless steel.
The right screw is needed.
Look here for ideas.
You need different screws for wood or composite.
Simpson Dexxter screws with twin threads are best for composite according to the video review at the link.

There is no competition, literally. Use screws, otherwise the wood will warp and pull all the nails right out. Screws are faster anyways unless you're using a nail gun. USE SCREWS!!

Screws. Don't forget the arch in the wood grain is on topside.

Screws.

Cover them with plugs.

Align the grain of the plug with the grain of the board. 

Screws!

 LMAO-it's not a black walnut cabinet!

Nick

Kind of looking at this for a re-decking I need to do:

nails!

Use torx not square. Square is almost as bad as phillips

Screws...they'll never back out by themselves and it is much easier to unscrew a board if you need to replace it

Torx screws all the way. And use an impact driver!

Maybe not black walnut, but where I live, a lot of decks are made of ipe and teak. 

I use torx for just about everything anymore.  I don't buy phillips or square unless they don't make what I need in torx

Use Deckmaster Brackets.
The deck boards are screwed from underneath.  No unsightly holes or splinters, and if you ever want to refinish it, you can sand to your heart's content.
I've always used them, and they make a regular deck look like a million bucks.

Screws.

I rebuilt my front porch 20 years ago.  The other day an appliance repairman told me I used the wrong screws on the deck boards.  He said I should have used the new coated deck screws, they won't rust.  I didn't bother to tell him that the heads of the screws were coated, 20 years ago when I installed them.  Not sure any of them would screw back up out of the boards if I decided to rebuild it again (porch/deck boards and frame are fine, the steps are looking bad and I figure if I'm going to replace the steps I need to go ahead and replace the porch/deck boards, too.  And the handrails.

I love this system, its a hidden fastener but you can remove and replace damaged boards anywhere on the deck.

They make deck nails.

They make deck screws.

They make screws other then deck screws that will cause issue when used in the wrong application.

They make nails other then deck nails that will cause issue when used in the wrong application.

The deck I built for my parents has deck nails, deck screws and lag bolts.

the nails are not coming out. 2 years so far.

if your nails are coming out on your deck; Your deck was A) built with the wrong nails/screws. B) lacks adequate support for the boards causing the boards to flex and placing enough pressure to remove the nails/screws, C) ground movement causing the deck to come out of square. D) your contractor sucked in some other area.

When you build your deck, do not be tempted to seal the bottom half to hide the structure completely. allow some air flow some how. So many contractors and DIY people do not think about what happens when you trap moisture/critters/whatever under your uncoated deck. unless you will coat every piece of wood on all sides before building the deck. even then it is a recipe for disaster.

My opinion is worth what you paid for it. I am not contractor nor a deck builder. I stayed at a holiday inn once and built two decks. both are still standing. one has a spa on it now. I noticed when getting quotes on the deck at my parents house, the cost varied wildly and seemed to have no correlation to build quality. Every contractor disagreed with the other on techniques and methods of building decks.

Edited to add: IF I had it to do again, I would build a PVC deck rather then real wood.

I tore my deck out five years ago and put in three yards of pea gravel. Fireplace in the middle, zero maintenance...very happy

Screws and  hidden fasteners.

Little metal clips that are driven into the side of the board and then fastened down with a screw.

And use as much stainless hardware as you can get.

The new rot treatments eat steel like crazy.

Coatings ALWAYS have defects.

THIS

Screw it.

Screws.  Slicing bare feet on proud nails sucks.

Hidden deck clips (many vendors now) and stainless screws.

There will be NO fasteners showing.

No holes to be plugged.

The clips go into the side of each board allowing the other side to be free to expand and contract.

The screws go into the joists and are UNDER the next board.

Face screws at more than on spot per joist does not allow for the wood movement that WILL happen.

Splitting from wet to dry and back dimension changes occurs.

If a wide board starts to warp the fasteners are NOT going to hold it in position.

They will pull right through the board if it warps upwards.

Those clips are great, wish they were available when I built my deck. I put down Trex right after it came out, used the twin thread screws that were recommended at the time. They don't look bad but the boards have nowhere to expand in the summer and composite grows more than wood in the heat, they sag between the joists which are on 12" centers and have pushed the trim pieces around. Some of that movement is certainly from the substructure but the decking itself grows and shrinks like vinyl siding. Thinking about taking it out and replacing it with a newer product using the clips.

Greatest thing since sliced bread