I own quite a few of the Malays Driftwood in all different shapes in sizes.Mostly for looks,but Bristlenose as well as certain other Pleco's actually consume wood and need it to have a well balanced diet.
The only con that I've seen,is that it tends to lower your ph a bit.
That won't be a concern for people who start with high ph's but I have low ph water ,so I always have to keep an eye on that.Adding crushed shells to some of the filters,has really helped.
Overall,a great look for your tank.

Pros: Looks very natural-- withstands tests of time

Cons: Can lower your ph-

We use this in our tank and it looks terrific. It holds up really well too. The natural look of the driftwood is appealing with live plants and gives a very relaxing look to the tank.

You need to watch the algae on them though--periodic cleaning (scrubbing) works well so long as you don't do it too vigourously.

Pros: beautiful

Cons: none

My python spends almost all of her time on one of these!!

Pros: My python loves it.

Cons: None

I had these in my aquariums for the natural look. Also some of the fish liked to hide under it.

Pros: Fish like to hide under

Cons: none

This makes the tank a little rustic looking and makes a place for some of the fish to hide.

Pros: good looking, adds decor

Cons: none