Honestly I like all three, I used to only like glass and metal, but recently the addition of a couple of Tantus toys and the L'amourose Denia and We-Vibe 4 silicone has been going up a lot in my likings.
So I guess for dildos my preference would be glass, metal then silicone
For vibrations it's silicone all the way - Purly because all the glass and metal vibes I have had have not been good at all.
It really depends on my mood - But I'm greedy I like them all haha
1. Silicone (although it depends on the texture too, I prefer softer silicones to hard ones eg- Vixskin, Tantus O2, etc)
2. Stainless steel/aluminium
3. Glass
1. Premium grade silicone (imho the best option for vibrators)
2. Glass (my favourite material when it comes to non-vibrating dildos)
(3. I would love to get a metal dildo one day, thinking I would really like it ;-))
Plastic is sort of okay when it comes to bullets.
I don't trust rubber and latex, being a person who is quite meticulous when it comes to hygiene - I prefer to have fewer high quality (and more expensive, obviously) toys than a whole cartload of cheaper stuff made from more suspicious materials.
When it comes to "skin safe rubber", I get a bit worried, too, because this term doesn't really tell you very much about actual chemicals that have been used, I strongly suspect various companies use different "blends" they refer to as "skin safe", having different standards about what is safe and what isn't...
We mostly have silicone toys and one metal one so I would say silicone but love the look of the glass dildos and been told lots of good stuff about them :)