I had a Bullet. The first thing is to learn the models:

UK made
Madras 4-speed
Madras 5 Speed iron engine
Madras 5 speed Aluminium engine
Madras EFi

Mine was a 5-speed iron. The tools issue is odd, you need imperial tools for the major engine parts, metric for the outer stuff . These things are labour intensive (2000 mile oil changes) and slow (50 mph cruising). They are also very simple. Mine had one loose connector and two busted clutch cables in two years and 12000 miles. I put this down to a massive improvement in quality at the point they went 5-speed and the fact I hardly modified it (did minor things like opening the exhaust and putting an extra tooth on the gearbox). The chap who bought it off me tried to make it do 70 mph for longer than it was meant to and it siezed. The owners treat them like mechano and usually want to try and make them into Goldies on the cheap, so Caveat Emptor. The EFI version to me would make a great RTW bike, they are low, easy to ride, simple in some places, massively reliable in others and above all frugal (I got 70 mpg with a Goldstar silencer and upped jets). Buy as new as you can and get at least 6000 miles in as practice for how these bikes ride. If you can live at the bikes natural speed and service needs you'll be happy.

I own a Hinckley Triumph Bonneville. They will prise this bike out of my cold dead hands. It is tough, efficient and easy to ride. They used modern materials with basically an early 1980's engine layout. Performance is similar to an airhead BMW, which plenty of people have used RTW. The 6000 mile service intervals and motorway performance are the big advantage over a Bullet. The tank is too small, 200 miles and you are walking. The tyre sizes are the same as an F650, so you can get knobblies. The paint will fall off the engine, which is useful to know when buying a two year old 1500 mile example from guys who've spent thousands on Chrome and less on petrol, little reaslising they had a true all round bike hidden under pictures of Steve McQueen on the posters.

I test rode a Scrambler. The guff about the 270 firing sequence making it more tractable was made up by a marketing loon, the loss of 10 HP is real. The high exhaust makes luggage a PITA. I'd still get one if there wasn't a Bonneville T100 available. Avoid the SE, the tyres are tubeless, but the front is rollerscate sized.

I'd say the choice has to be based on what you know. I prefer FI to carbs, don't worry about shims instead of pushrods and as I don't get out of Europe find 80 mph two up cruising useful. For a solo RTW where most things run at 40 mph I'd have to think hard about the Bullets range and frugality against what I know about Triumphs.

I wouldn't join the Tiger XC testers club for at least 18 months!!

Andy