Re post - I got caught by the Edit Timeout and need to clarify a few points, spelling etc...
Sorry to hear your experience was so poor with your Infinium. I'm not sure it was made for smaller people, or Americans (meaning Americans are smaller or American soils?) per se. The reading I've done indicates it was designed/tested for/with Australia's highly mineralized soils. I'm 6' and I have a few extra notches to extend the lower shaft farther out. At 6' 6" tall, I would have expected the potential for issues regarding shaft length. I have a very good friend who is 6' 7" and he has to select even the car he drives based on the restraints of his height vs. the general population. I've never been to Australia, but I suspect you're well above average height. Garret makes an extended lower shaft for taller people, and although I've not priced it, extra regular length shafts are about US$10. It may be worth the money to research this, and remove that frustration.
The control box is designed for three different mounting configurations, two of which allow for the writing to be oriented upright. I'm not sure with having such mounting flexibility, it would be possible to always have the writing upright however. I agree that It would be nice to have the momentary Iron Check switch that you, and others, have mentioned.
Pulse Induction detectors like the Infinium are known for their strong attraction to iron, and also for their inability to reliably discriminate iron out. I'm not sure if you stay with a PI detector of any brand that you will have any better success in dealing with the iron; The trade-off is superior depth over VLF detectors in highly mineralized soils such as those found in gold fields. Through experience, your ear can become an excellent discriminator of various objects passing under the coil. There are a number of great "how to" articles on this forum if you scroll down they should stand out, and they may be of assistance to you.
Garrett is well known for their excellent customer service and equipment; Far from being a "joke". Perhaps your single outing and I presume limited experience with the Infinium has added to your frustration. PI's do have a much steeper learning curve in my experience, than the more popular VLF machines. What other machines do you own/tried, and how did they compare?