I would prefer a voicetool for one simple reason: it is perfectly usable in game. It makes syncing (if watching tutorials/demos together) way easier. You can say something which came into your mind instantly. Well, I dont see any downsides using an voicetool, except for some languague issues. But maybe we make groups for country´s, if there are enough people who would like to join that.
Here is an short overview how a game session could look like. I think that testing one game will take ~2 hours. We would go through the menu and set up our configs. Afterwards we will watch available tutorials (of course only demo/video tutorials). I guess this part should take about 20-30 minutes. Afterwards we will test the weapons and mods (aye, Fragging \o/). This will be obvious the biggest part, I guess something like 1 hour. When we done with it we might watch one or 2 demo´s of their better players, to see the game max potential. Then we only have to summarize the good things which are interesting for us. If such a session had any success, we will continue with another game on an another day.