Wood decks are not nescessarily slippery when wet and with proper care maintain their beauty thru exposure to weather ...there are so many qualifying factors that effect performance that without knowing your situation there are no cut and dried answers..the main thing to know if you are considering other options is that wood can be re- finished...repaired ...revived...the other options usually just have to be replaced when problems arise

Many thanks ritasj. We are building a house on a hill using existing structure. the street level is higher than the back. Our common living area is on the top level so we have the possibility to have a terrace in the sky so to speak. It will be exposed to elements and we have small kids hence the two concerns I mentioned. I love the beauty of a wooden terrace but my husband is less enthused. I was therefore wondering what to look out for in terms of these two factors (I.e. is the slippery factor material or maintenance dependent and how labour intensive is the care?) Not yet having started the research, I was hoping for some reccomendations on material considerations and some definite dos and donts while we contemplate, and before I end up choosing a cold tile option. The shape is long and rectangular, maybe about 30 Msq and runs along the back of the house, from kitchen, past kids play room and terrace can be accessed from both rooms (floor to ceiling window walls), Interior floors would be hardwood.

Max...the maintenance is not overwhelming...usually once every year or two... clean and re-apply a protectant sealer is enough...the slippery part is not usually an issue if you design your deck to drain well so that it dries quickly...also the use of decorative outdoor rugs and furniture arrangement can be a deterrent to tempting long stretches for running in...given the height and danger element of the penthouse deck of course the railing is very important if you have small children...one thing most people don't realize the value of is the need for shade that can easily change with the weather...also planning for different shade areas for different times of day...I find shade cloth over a wooden pergola over areas where windows are work well because they are easily removable in winter to allow sunshine in when you need it...an area with solid roofing for dining and to have a nice spot to go out even when it is raining ...lighting can be installed easily in this area for evening entertaining..we even watch tv outdoors ...all of these shaded areas protect the deck condition as well...
The terrace will be an extension of your home with a shorter time frame for usage so furnishing it comfortably and providing areas that are comfortable at any time of day will be worthwhile efforts to maximize what can turn into you favorite place to be ...
One other factor to consider is privacy...and storage...if there is room these two can work together....you will need weather proof a place to put things away in the winter and stow things easily if it rains...privacy walls at the ends of the deck or space under the eaves can have weather proof storage so that you can store and protect things without having to carry everything down to the basement...
Also in furniture selection ...quality...comfort...and lightweight are foremost..being able to move things around easily into or out of the sun makes life much easier..and if you are ever lucky enough to have an hour to relax you will be glad you got those high quality cushions and furniture

Thank you again for a super detailed response. Definitely points to consider! I especially liked your first comment regarding the overall lifespan of the wooden decks vs alternative materials. I am looking forward to it, and will share pics once in progress/completed.

Looking forward to seeing your project..as we live a completely outdoor lifestyle at our summer home ...we have made all the mistakes and love to share our solutions and enthusiasm for outdoor living...