OK, I'm not a guy but I used to work in a sex shop so I like to think I'm fairly well versed in these things. You need to think about a couple of factors:
1. Budget: As the Realdoll thread demonstrates, you can spend anything from a couple of bucks to many thousands of bucks for a toy.
2. Discretion: If you need to hide it from family/friends/SO, a smaller toy is always going to be better. Ideally something you can chuck under the pillow if caught mid-act
3. Hygiene: This is the big one for me. Toys are a breeding ground for bacteria and the idea of putting anything near my rude regions that isn't clean freaks me out. Silicon is easiest to keep clean (you can boil it in hot water) but is more expensive. Anything with a non-removable battery is hard to clean.
As you've said, beyond that it comes down to personal preference. The best selling products for us were jelly type toys (can't post links as I'm at work); they're cheap enough and very stretchy. Fake pussies also seemed popular (you know, the big ones you lay on the bed) but seemed really inconvenient to me.
Whatever toy you go with, remember you're not going to get a free ride
like we ladies do - with most toys, you still have to put in the legwork yourself. For this reason, you might find it an enjoyable novelty but it's likely to end up languishing in your sock drawer in the long term
