3 3/4" is what I prefer....I get annoyed at 1:18 stuff. Scale purists contributed to making modern era stuff incompatible with 20+ years of ARAH stuff, then they complain "We need a Sky Striker that can fit modern figures". So you got companies saying they make 3 3/4" but are really making 1:18 stuff. What's compatible is debatable and based on personal preference, of course.

12" has become priced out of existence for the most part, that is with cloth clothing, not some shampoo bottles. The last great age of 12" at retail was late 90's/early 2000's.

6" limits what vehicles can be made. Vehicles were a big part of ARAH. $20 per figure is too much for me to ever care.