I agree with vicious. You defiantly need to go to a scenario before you decide to jump into it because it isn't always for everyone. One of the hardest things I encountered when first transitioning from airball to woods/scenario was that the pace and timing of the games are a lot different. Most airball games are no longer than 10 minutes max, it's constant shooting and aggression. Playing scenario, I came to learn that the game is not entirely about shooting out the other player. You have missions and objectives to complete which reward teams way more than getting the most eliminations. This means that there are times where there will be no shooting or contact with the other team at all, just moving around the field. It's a very different way to play paintball.
As for vests, I recommend special ops paintball every time. I have tried out numerous packs and vests and it seems that the one I've become most comfortable with is the special ops series. Most of the vests sit in the $70-100 range, and are custom made. There's multiple types of pre-made vests to purchase which cater to anyone from a light role to a heavy one. There are several different options for 'do it yourself' vests as well, they give you the option to custom the vest to your liking with whatever attachments you see necessary. It's a little more expensive to do that, but it all comes down to personal preference in the end.
As for BDU's, I recommend BT's Pro Pants. I've worn a few different brands while playing paintball (Empire, Dye, Special Ops, etc...) and I have to say that I've favored BT's the most. They are extremely comfortable, and when it's hot you have the option of unzipping the sides revealing a mesh material that allows some air flow in. They also have adjustable knee pads, they pads are thick and keep your knees from becoming even a little scratched or banged up during a nasty fall. What's also nice is that the pads are adjustable, you can fit them to where/however you feel is comfortable to you and then simply velcro the straps together. One of my biggest worries was that the velcro would come undone in game, but to my surprise they never have even come loose. The matching BT tops are also decent, it's nice to have for cooler/colder weather but not needed.
As for what marker to buy, like vicious said it's all about preference but I will once again agree with him on the Tippmann Phenom. I have used countless numbers of different guns, and for this being a Tippmann, I must say I was surprised at how well it compares to some tourney markers. It has five different firing modes not counting semi which can be programmed for use into the board (I will say that it's a bit hard to get the hang of at first but eventually you'll get it) as well as a changeable firing mode (ranging anywhere from 6bps I believe up to 30). Also like vicious says, it comes in the the built in cyclone feed which is good for cycling balls up to about 20bps unless you purchase some of the TechT upgrades. The gun has zero kick, and I'd say it has more than just pretty good efficiency, however I don't recommend using CO2 with it, stick with HPA. And, because it is scenario and the games tend to be long, a larger tank than normal isn't ever a bad idea. I run an 88/45. Gets me through almost two cases before I need to fill back up. Make sure when looking into getting a vest that you get one that comes with a horizontal tank holder and then search around for a coiled remote. It is defiantly worth investing money into. Keeps your setup A LOT lighter. I know CP makes an excellent one, I've owned it for over a year and I've never had any trouble with it to date.
I hope that helps and gives you a little better insight to the scenario world and what gear you should look into. Also so you aren't searching around for the websites either I'll give you the links...
- Phenom (I don't know if you can buy direct from Tippmann but at least you can see what the marker looks like and get a better description)