My order of preference of charter airlines (as charters, not the scheduled equivalent):
1. Excel (best flights I’ve ever had)
2. Air Scandic (very impressed with the service)
3. Thomas Cook/JMC (JMC better than TCX)
4. Airtours/My Travel (varied from aircraft to aircraft)
5. Monarch (excellent scheduled service)
6. Britannia (OK)
7. Air 2000/First Choice (disappointing)
8. Air OPS (frankly appalling)
This is just my opinion of course, and I know several people who like First Choice, maybe we were unlucky.