In fairness to all, I have been away with probably all but Gower, and they're all the same.
Completely Pot Luck.
I've had great and terrible tours with most companies, some in consecutive years, and the blame can't always be identified!
In my experience (approx. 2 trips a year for the last 13-15 years, from youth bands to the top flight), a good driver and bus are THE most important things, and getting both at the same time is very rare and both are just subcontracted from the main company, so pot luck.
Venues can be misleading. I'd rather play outdoors to a square full of passers by, with a gradual build to 3-400 people, than to a concert hall with 30-50 in (not unusual on a tour), but that's personal opinion.
Also, what they do with the free time is important. Some tour companies seem to neglect some of their passengers, ie. nothing to do for youngsters on a youth band tour (no football, hotel with no gathering point or "common room") or, even worse, no bar or facilities for older ones.
REALLY thoroughly check everything before you book, the accomodation, venues Bus, driver if possible and then pester the company 'til you leave the country!