I don't agree that hybrids sound like accordions. The sound is affected by other aspects of the construction besides the reed itself, and they have a sound of their own. However it is true that they don't sound quite like traditional concertinas, but it's a matter of personal taste whether that matters. Different isn't necessarily worse. I've heard good hybrids which to my ears sound better than an average traditionally-reeded instrument. The question of reeds aside, he quality of construction of a new hybrid may be better than a 100-year old instrument which has seen continual use.

It all comes down to what style you want to play. If you just play melody (Irish music for example), which is principally played in the middle range of the instrument, you may find you make little use of the additional four buttons, and a traditionally-reeded 26-key may well be a better solution than a 30-key hybrid. On the other hand, if you play chordally those additional buttons come in very useful, especially on the left hand but also on the right, and it may be worth accepting a small compromise in the tone in return for that greater playability.

If an instrument doesn't meet your particular needs then being cheaper doesn't make it good value for you.

For what it's worth, I play 'English harmonic' style, rather like Brian does. I have a 40-key C/G and a 31-key G/D and I make use of all the buttons from time to time, including the 'squeaky' right hand ones but particularly the low notes on the LH accidental row.