I was on the fence about applying for this card, but was in the midst of planning for a vacation and remembered the limited-time vacation rental credit, so I decided to apply and was instantly approved. I've never stayed at an Airbnb or VRBO, but spent some time perusing different properties. Then I saw your post and was curious if it would also work with rent payments.

My apartment allows electronic payments through APPFOLIO. https://www.appfolio.com/
They charge a 2.99% processing fee for credit cards, but I decided to take a chance and made a $195.00 payment with a $5.83 processing fee. The charge posted on December 26 and the vacation rental credit for $200.00 posted last night on December 30.

I would've definitely found value from VRBO/Airbnb, but using it for rent lowers the effective annual fee to $200.00 ($395.00-$195.00). I doubt the signup bonus will ever get any better than now.

My thoughts on the card:

I applied on December 25, verified my identity and got the virtual card number through the app on December 26, and accessed the travel portal.
I don't like booking flights through 3rd parties, so I made two hotel reservations.

The first was for a stay at the Wyndham New Yorker hotel near Penn Station/MSG. The portal price was $161.00, which was cheaper than booking directly with Wyndham ($186.00) EXCEPT it mentioned a $40.00 resort fee to be paid on arrival. I had a planned a two-night stay, so I booked the first night through Wyndham and the 2nd night through the portal. If I am able to get the $40.00 resort fee waived on the 2nd night, it'll be a good deal, but, if not, I am effectively paying more and also forfeiting my Wyndham elite benefits and points.

The second was for a stay at Home2Suites Milwaukee Airport. The portal price was actually $15 cheaper than booking the best available rate with Hilton, though I am sacrificing my elite benefits and Honors points. To be fair, both of these hotels are mid-tier, so wouldn't have expected many elite benefits/upgrades to begin with, and I am earning 10X points on hotels through the portal.

If you are booking flights or higher-end hotels, it'll be easy to utilize the $300 travel credit in one shot, but lower and mid-tier hotels may take 2-4 bookings. I actually spent $20 more at Home2Suites ($4.00 beyond the $300 credit) to utilize the entire amount without having to book a 3rd stay. The additional 160 (20x8) miles and larger room should make up for the $4 overspend. As a side note, even the premium room was $17.00 cheaper than booking with Hilton direct.

I don't know if I'll keep this card long-term, but is a great option for non-bonus spend. I currently utilize Priority Pass through the Chase Ritz card and have 6 authorized users, so many of my Venture X benefits are duplicated. I'm also curious how long it'll be before Capital One either increases the fee or reduces benefits. From experience, it is harder to cancel a card when you have multiple AUs that are utilizing and enjoying the Priority Pass benefits, even if the annual fee goes up in the future.