Adding a generally positive HVMB experience here:

We booked a 4 night stay in Portugal during the early May 40,000 bonus promo. The local agent was Feel Porto and they were very responsive via email, WhatsApp, and their web platform before and during the stay (WhatsApp messages were answered within a few minutes while we were in Portugal). We had a confirmation email from Feel Porto within 24 hours of booking via Marriott with a login to their digital key platform. They resent the email and followed up proactively with the door code prior to arrival. So everything was smooth from a pre-trip logistics perspective.

The apartment itself was great, super clean, very well furnished, and as close to the pictures as you can expect. Would happily stay there again.

The only drawback of the experience was that the booking did include a 200 Euro security deposit which was not automatically returned. MB points were also not timely credited. We did end up getting both back quickly once I reached out. This was the timeline:

June 28th - Checked out
July 18th - Sent a follow up email to HVMB support
July 21st - Received email response from HVMB saying they have submitted the security deposit to be refunded within 5-7 business days and that elite night credits and points will take 4-6 weeks post departure to reflect on my Bonvoy account
July 24th - Security deposit refunded to CC
July 27th - Stay & 40K Bonus points added to my Bonvoy account - Note the HVMB nights count as Bonus/Promotional nights, not nights stayed

So overall, a positive experience. Bit annoying to have to chase them for the deposit and points, but it was only 1 email and resolved quite quickly. I would stay at one of these again depending on location.