You might consider contacting Dr. Hsu and seeing about confirming whether auditioning his units for a period, with an option for return if not satisfied, is feasable. If so, you may well find that they fit the bill...for a much smaller one than the fine performing RELs. Many factors will dictate their performance, notable among them the quality of the crossover which, in the case of the Hsu's, may prove to be an issue of compatability both up and down stream upon audition.
As far as Dr. Hsu's general designs possibly being of a HT bent, rather than being more suited for music reproduction, I would attest to their being -- at the very least -- dual use, if not having a definite bent towards music. Moreover, the fact that these designs can rather efficiently meet the requirements of most HT applications is a testament to Dr. Hsu's engineering. However, don't mistakenly consider his designs as primarily HT performers. Rather, I believe that most owners of Dr. Hsu's designs, such as I, will also attest to their respective Hsu model's fundamental musicality, as well as ease and versatility in mating with main speakers. Such performance at the Hsu's price points are a real audio bargain while admittedly his units' componentry and level of finish, as has been pointed out, are no doubt areas where some of the savings passed on are reaped.
FYI, in case it may help in your assessing my comments, I utilize a pair of Dr. Hsu's original 7' tall upfiring 12" passive design units(flat +/-1db to 19Hz) powered by a Kinergetics (Class A) amp crossed over through an active crossover (Krell KBX) in the mid-low 30s from a Krell KRC-3 which, above this, also runs to a Krell KSA 200S on to B&W Matrix 802IIIs run full range. Not a hint of HT bluster.... All good luck to you.