Depends whether you like theme parks and roller coasters! I do and I love Alton Towers and go quite regularly but then again, it is only 12 miles down the road from me ;)
AT is in the middle of a rural area, served by narrow country roads - once the coaches start queuing, you can sit for hours, so get there early to get parked before the rush.
For most rides at Alton, their is 2 people per row or car. But their is exceptions.
Air, the flying coaster seats 4 per car.
Nemesis, the inverted coaster seats 4 per car.
Oblivion seats 8 across per car.
Ripsaw seats more than 10 people per row.
Submission seats 4 per row.