I have owned a Vango Beta 450 for 3 years now and have had no problems with it at all.
It has a huge porch, roomy bedroom for a 4-man, and goes up in about 10-15 minutes.
We go to a lot of festivals (2 adults and 2 kids) and find this the perfect compromise between having a huge spacious family tent and wanting something quick to erect and small enough to carry from the car park.
I have used it in all sorts of weather. When it is hot you can open both doors for a cooling through draft. In gale force winds and rain it has held up with no problems, and it has never leaked.
The only downside in rain is that when you open the door, water from the roof will run down onto the groundsheet. I don't see how to rectify this easily without adding a new pole and eave to the design. We just take an old towel to mop up the drips and that works fine.Vango Beta 450 4 Person Tent - Black/Excalibur