I would recommend a well-maintained used YTS-23 if you're starting out. Find a reputable dealer who can service the horn and make sure it's in excellent shape. Most importantly, get a qualified teacher to help you on starting out.
I don't have experience with the Trevor James horn you mention, but they are generally a well-regarded company that makes a quality product. I got to play one of their SR altos and it was an excellent horn. Most people seem to compliment their pro instruments as well.
All that said, a solid YTS-23 will be your best bet IMO. Best of luck and welcome to SOTW!
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