I love the AlexB VTD bundle... the C2B if I want to reduce high frequencies (really love what it does to a voice with too much high frequencies), the C2A for smoothing a guitar.. and the AlexB Chandly CLG for all kind of stuff... but mostly for stuff that needs punch like a rhythm guitar.. but that's just because I mostly just need stuff for guitar and voices... for sure great for all kind of mixing purposes.. I think the demos are great.. you will hear what you can expect..
Sum 100a leveler V2 is really good on vocals so is the Opto 3a with the LA-2A preset the combination of both is really great
but if you can only afford one at a time i would go for Sum 100a leveler V2 first as this thing really blows me away with the amount of compression you get with this beauty 2nd get the Opto 3a for vocals
if nice top polished sheen is what you want on your vocal the Flucti Mew is also a great tool to have
But the highest recommendation goes to the Sum 100a leveler V2 for vocals from me if i could only have one
for master the Flucti Mew Rocks , really nice finished sound and nice glue but Sum 100a does a good job as well, i just prefer the Flucti for my taste
both Sum 100a leveler V2 and Flucti Mew are nice on buses depending on the needs, its best to have both because they got very different tones and i really think they compliment each other very well in a mix