For something to replace the PA38/C152 as a reasonably inexpensive 2-seat trainer, one is spoiled for choice right now. But, off the top of my head I'd look seriously at the...
Aero AT-3
Sky Arrow
Slingsby T67
Liberty XL2
And that's a tiny sample of huge numbers of aeroplanes on the market that are newer and nicer than a 35 year old C152! Which is not, of-course, to criticise the Boomerang, which is almost certainly a great aircraft, and best of luck to it.
G