Alex
I would agree with you that all door to door vacuums are overpriced. But, if you have the salesman in your home & you're ready to buy, that's why you haggle him down as low as he will go. Even go onto Ebay or other websites that have newer secondhand models, & threaten the salesman if he doesn't lower his price, the website gets his business & not him. And like you said, if he doesn't give in, then buy secondhand & save some $$$.
As for seeing too many of the Sirena vacuums coming in for repairs, the hose being too short & the powerhead too cheaply made? Well, let's be realistic here - What would you expect from a vacuum that's Made In China with Globally Sourced Components & a Italian motor? Heck, the Italian motor right there should give you a clue as to it's build quality....some Italian made products are good, but most are cheaply made, overpriced junk. For that reason alone, I would be suspect of it's build quality. Plus, it's Made In China & it sells for 1/3 the list price of a Rainbow. How can you possibly compare the quality of the Sirena to something that sells 3x the price? You can't!
As for not liking the powerhead, that wand & powerhead neck Sirena uses now looks identical to the Wessel Werk central vac powerhead neck & wand that is used in central vac hose kits, with some slight modification to the top of the wand to fit the Sirena hose handle. I would be willing to bet that a Wessel Werk EBK340 or EBK360 direct connect powerhead should be directly compatible with that wand, no modification required. Also, maybe you don't remember this, but back a couple years ago, about a year after Sirena first entered the market, they offered a black Premium model with a Plastiflex hose, wand & EBK 360 soft clean powerhead with direct connect wand. I would be willing to bet they carried over the wand to their original powerhead with slight modification to the top of the wand & of course new powerhead neck.
Rob