Standard sized preferably, if I had to choose a plus sized ken it'd be the Slaydawg size. I'm definitely partial to the RWB Classic, Kaizen 2.0, and GT-1/1-5 shapes. To me they are the most visually appealing and have great balance, not sacrificing play in one area of tricks to boost play in another (i.e. sacrificing lunar play to increase slinger action), at least not too much. As for woods, my go to woods for kens are definitely hickory and maple woods, depending on what the tama is (natty or painted, what paint is used, colorways, etc). Ash would be a SUPER close contender too, but I definitely enjoy the play I get from my maple and hickory kens the best.
For anyone who likes the Craft Slim shape, could you tell us why? I personally didn't like playing with it but what do you like about it?
Good balance. Like @Gasiek said the NextGenHG is a great ken. I have a soft spot or the RWB classic. Simple and elegant design. Wood type is something else I look for. @KeeganS I am also on the hickory fix (RWB classic, HG, Kotodama). The skateply LBB is by far the best all around shredder I have. Everything is sized up perfectly on it!
Slim ken / sarado, medium to big cups, 0-5% larger that standard, a swoop, and nice cup rims. My Craft Slim Plus and Aynedter mod have almost all of them. My current favorite ken shape, the Grain Theory Aynedter mod has: A slim ken and Sarado for Slingers, Big cups for lunars, 4% larger feel for juggles and kenflips, A swoop for increased lunars and juggle flippage, Cup rims to lock in stalls and underbirds, And a 1.5 base cup cone for lunars and taps. Seems like an all around dama to me!
Don't know that I've found the "perfect" ken shape but texture is something I notice right away. Some kendama brands tend to over finish their kens and they're just slick. I definitely prefer kens with some texture. The over polished ones feel more like a furniture leg than a kendama.