We vibe 4 vs we vibe 3

I rcently bought the we vibe 4 and it's good. But sometimes i wonder if i shoul of go with we vibe 3 as i feel it is a little bit too small.
Does somebody have (or had) them both and could give some comparison? I dont want to mess around and ask LoveHoney to exchange for 3rd one just to realise that 4th one was better.
Any advice?