I've camped for many years (prior to getting our bus) with a gazebo. Over those years, I've had a number of different gazebos, starting with ye olde "pooh" pipework ones all the way up to a pop-up gazebo. This is in preference to some kind of awning (either tent of bus awning). Whilst some people get on with awnings, we just find them an awful lot of faff, and even the drive-away awnings you have to detach in order to drive-away. More faff. My preference (and everyone's mileage is different - no judgement here!) is to be able to step out of the van into The Outdoors (with a roof for when its raining or - no laughing - too sunny). Personally, we don't need extra sleeping space. So we use it for shade and to keep the rain off, pretty much. It also declares to everyone we're camping next to, "This is our spot", when we do "drive away" in the van.
A couple of years ago (whilst still tent camping), my mate pulls out a brand new Coleman Event Shelter. Once put up, it's very, very impressive, and is very nice. But.. BUT!... putting it up was - you guessed it - a complete faff! They're all but impossible to erect if there's only one of you, and even with two people it's not the easiest thing on the planet (as you're putting it up, it all wants to collapse on you right up until you get the very last pole in place, at which time it then becomes solid as a rock). And the bigger the shelter, the bigger that problem becomes. Oh, and packing the thing away can be a bit of a ball-ache as well; the poles are all curved (and attached to each other) which means you have to ensure they're all "folded" in the same orientation, otherwise you end up with a mess that won't fit in the bag; this part sounds ridiculous, but it's not until you're stood there with an armful of curved bars trying to get them all in the same orientation that you realise how much of an ar5e it is.
I'm an advocate of The Pop-Up Gazebo. They pack up perfectly into a rectangular bag that - in the case of the one we have - fits millimeter perfectly across the back of the boot space in a Westfalia conversion. Even with only one person erecting or breaking down, you can have it out of the boot and up within just a couple of minutes (great for when you arrive and it's raining) - if there are two of you you can have it erected in seconds. The only real issue that we found with the pop-up gazebo is that in a stiff wind the concertina-like bars along the top edge of the gazebo have a tendency to bow, sometimes to the point where the bolts that hold them together (not the bars themselves) can bend! (they do like to use cheap bolts to begin with). To counter this I take a bag of spare nuts and bolts (high quality) as replacements as and when required, and I also added in additional guy ropes in the "middle" of the concertina edges; for use when the weather really does turn to utter crap or I've camped in a particularly windy area. This strategy has worked without fail so far, and its been in high winds for years now without bending any more bolts
So... event shelter or gazebo? I'd go for the pop-up gazebo every time, because it's just less faff. And less money. Way less cool looking, I'll give it that! To top it off, the inside corners of the pop-up gazebo lend themselves well as small shelves for speakers, solar-panels with phones attached etc, and it's much easier to convince a wet micro-fibre towel to stay put whilst drying than over the curved edge of an event shelter.
Apologies for such a verbose reply; as you can tell, I don't feel strongly about this topic, right?!