I gather from what you wrote that you probably have never really used either a bucket truck or a spider lift.
There are merits to both of them and the perfect lift has yet to be built in the world. Bucket trucks are good if you are on a street and have lots of elbow room. That is rarely the case in private tree care in a back yard. You always wind up in tight spots, places that a truck that is 2.6 metre wide (8 1/2 ft), a lift that sits on a 16 tonnes lorry, and is 10 metres long, simply cannot go places. Even if you do get there the booms are so long, you can't even unfold them. The problem is even worse the minute you use a bigger lift in the 23 metre size. Our trucks are much bigger and heavier in the US, causing a tremendous amount of damage to lawns.
Spider lifts are a great alternative to reach difficult places, as you already know they are slim, light and very maneuverable, and as you will see, cheaper. a 23 metre truck mounted lift costs around
USD$135.000,00, not including four wheel drive which adds another USD$24.000,00 and up.
I am well aware what is available in Europe, however nobody wants to come to the US because of the way our legal system is here where you can sue anybody anytime at a drop of a hat.
The product liability issues are enourmous and add 30% to the cost of every piece of equipment in America.
Hence by the time you multiply your British pound or Euro by our dollar add the product liability to it, Teupen spider lift prices are nearly the same as what they cost in Europe.
I have already checked everybody out in Europe in the past two years. Teupen Spider lifts are light years ahead of the pack in engineering, are safer, lighter and far better. When it comes to cranes and aerial lifts the Germans are the world leaders.