I really like my SDC2300, especially for traveling! In the Arizona gold fields I haven’t felt the need for anything else, but that machine is also tailored to the type of detecting I do, and the fact that a backpacking trip is never out of the question. It’s also essentially ‘turn on and go’. That said, the 4500 would be my choice for adaptability due to the ability to change coils. In a new area, a small coil like the Joey, and 8 or 11” commander, and one larger coil in the 14-17 range for the deep stuff and he’d be set. Oh, a lightweight battery setup such as the RC options people get for these...oh and a ‘screamer’ type speaker...etc...etc..lol. Or he could pick up a Monster for much less money and still do well. What are people using where he’s going? What do THEY consider best for the type and depth of gold they typically find? The gold monster is financially a very safe choice at ~$800 while the others could be several thousand. Is this a once in a lifetime chance to make a haul? Money is no object-get a GPZ and LEARN it first.