Sorry, kneeman, don't use either one but if I were to get one, I'd go for the first one - it looks more stable. The second looks a little cheesy for my liking.
I've used the "Bracketron : Dash-Mat Portable Dash Mount" for a GPS unit I had. Depending on your dash, neither may work well. On my dash it worked perfectly, on my ex girlfriend's, it was slipping and sliding all over.
If you can give up a few inches of A/C vent space... the vent clips holders work well and are fairly cheap in lots of the regular places. Measure your width and most "Universal" ones will work. Stuff on the dash scares me cuz I tend to take the corners maybe a little faster than... oh well.