For me, it's kinda tied with the Mario RPGs and Zelda series right now, with my choice of favourite depending on what I've been playing the most recently.
I prefer the Sonic and Mario series more. Though I prefer it over Kirby and it's definitely my favourite Mario spin-off.
The thing that I love about the Wario Land series is how innovative it can be. WarioWare though? The first was but the other entries feel a bit too similar layout wise, especially from Touched and onwards.
Unfortunately not. I have very little interest in Warioware, and that's all the series is anymore (Get it Together is the only one I've been able to get into at all, since it actually has playable characters, but that still pales in comparison to my interest in platformers, which exceeds my interest in everything else by a thousand fold).
The Wario Land games were peak though. In an alternate universe where Wario stayed a platforming franchise it would no doubt be one of my top favorite ongoing video game series.
Without a single doubt in my mind. I have loved the games since I was a kid and had the two Wii games (Smooth Moves and Shake It!) as my introductions to the series and loved every moment of playing them (although some of the missions in the latter are a little on the difficult side!). The concept of the frantic microgames in the various art styles with likeable characters while taking advantage of Nintendo's new hardware is a brilliant concept for a series, and the platformer games of Wario are a great counterpart to the Mario platformers which each of them having their own charm and great soundtracks and emphasis on GREED. I just cannot get enough Wario and I have easily sunk more than 600 hours in WarioWare Gold. Wahahahahaha!!!
Wario Land is one of my favorite game series, something about them just captivates me... plus the fact they star Wario, who I have felt attachment over unlike most other characters I know.
Similar reasons to Waluigi here, it does get a few points knocked off due to being all WarioWare these days, but I still love what we have!!