Big Al was one of the first Vocaloids I was introduced to when I joined, I had lurked around since his first announcement was made and witnessed the positive vibes fans gave him. (too bad it didn't last due to the anti-Engloid fans being so bias).
Tonio I liked after hearing Giuseppe's demo songs, it doesn't take much to realise how beautiful he can be - when you use him right. But... He rarely is so its a rare treat. I like male vocals, and Tonio's is my favourite because of how pretty it can be.
I generally liked the Engloids because I had to do a lot of research on the engine in V2 and V3, and I found myself just defending them a lot as a Engloid fan. The amount of crap invented by fans who hated them was silly. It could get quite personnel and I think people said things knowing I'd respond. A lot of the claims that were made turned out to be misconception, misperception or just made up on the spot to make Japanese Vocaloids sound or look better because someone felt they were. Big Al and Tonio are my favourite of them. I do have Japanese Vocaloids in my top 10, but I gave up on the anime stuff in 2006 so my interest is thin. This is why I take offense when someone calls me a weaboo. I don't follow the Japanese side of the franchise and the only anime left I watch/read is One Piece. (I stopped being a fan of anime/manga, I never stop being a fan of One Piece and watching/reading one thing does not make you a weaboo).
Nana is a much more longer story and has nothing to do with that. I first heard Nana in UTAU in 2010 and I wasn't impressed at all. The voice was dull and uninteresting. I did however start getting concern because of how freely western fans share the files. I started pointing out that you need to own the software to do that only to be told "its fine as its open license". Basically, the story goes someone was misinterpreting what that meant and thought "open license" meant you could free pass her around because you didn't need a license ownership to use her. It doesn't mean that. What it means is so long as you use her as a sample package, you can use her with any software as she isn't "Proprietary software". So you could use her in UTAU because of the fact you are still using her for the intended purposes. This was actually the first ever error spoken by the fandom I found myself correcting. Well when I took over bureaucrat here I was trying to get all the non-Vocaloid topics off the wiki and on to their own wikis, I think it was Bunai who argued some things had to stay. Anyway, Nana was given her own wiki and all information except some basic stuff was shifted over to the new wiki. I then had to follow this up with actually researching the products. This is when I heard the first instance of Nana singing in G.Band and Reason.
youtube.com/watch?v=v_o3I3LGiig
In fact this is the song that sold me on Nana. She sounded different in Reason and G.Band and this is what the Vocaloid Nana is trying to recreate. Thats why when the UTAU fans started complaining I said there was nothing wrong with the results. This is the Nana we were MEANT to have. I guess there was a little nostalgia in me from the 80s and 90s vocal synths that came out because of how crude it was. It was not attempting to sound human.
By the time I finished witing a lot of the content of the wiki I was a fan of Nana. I don't go for high pitched vocals at all normally. So she is my dark horse. ^_^'