For me, it's how the ball feels off the face and what does it look like when I am standing over it.

I look for how it looks to my eyes when looking down at it ,how it feels in my hands,how the ball rolls coming off the face and hearing the sound when it does jmo

Most will go by aesthetic of the shape,

Working with a fitter, we establish the correct length and the amount of toe hang. I tend to go with mallets as I need a longer sight line.

10 years ago, most mallets were face balanced. Now that there are varying amounts of toe hang available, there are several that work for me. The 7.5 model works for me. I have 1 each LH and RH.

Honestly, whether it's right or left handed.
Second is how it swings with my eyes closed. Gotta have that certain "feel" to it for me.

I look for feel, pleasing to the eye at address, and the moment of impact has a comfortable hit. I also examine the grip, knowing it can be changed, to see if it feels good in my hands.

Cheers!

I prefer traditional looking putters with no inserts. I've always used an Anser 2/Newport 2 style putter. I really wanted a Scotty and bought the 2016 model that had an insert. When the Special Selects came out without an insert I had to get one and gave my old gamer to my dad. But yeah, above all else, a putter needs to look and feel good to you. Confidence is everything.

How it lines up, the feel and the sound the ball makes coming off the face.

Chuck no question, absolutely!

I look at how the putter sits at address. I then check the feel. I don't like mallets but that is only my opinion. To each his own. Putting is the most personal part of golf. Everyone wants something different.

For me it's a couple of things.
1. How does the putter look and feel at address? Is it visually appealing? Does it feel good in the hands?
2. How does it feel when striking a golf ball? Does the ball come off the face hot or jumpy? Does it feel solid or mushy?

If it passes both then I may give it a try on the course.

How it feels in your hands, the weight, the balance. I also have never understood how anyone get s putter that you can't pick a ball up with LOL!

How it feels and lines up. I need confidence looking down at the putter. And that’s really why I have played the same brand for over 25 years.

I look for how the club feels in my hands weight wise. I do like having a milled face as well as it helps with distance control.

For me, it comes down to 3 things; how the putter head looks at address; how the ball feels off the face; how it feels in my hands.

agreed! These are important...

Feel is most important. Second for myself is esthetics. I went recently for a fitting and was fit into a Golo. I really didn't like the look of that putter. I have always used a blade style. I tried the Phantom X 7 and I absolutely love it! To me it has the esthetics of a blade with the performance of a Mallet.

I think the look is important. If you don't like the look of the putter, you won't use it or won't be confident in using it.

Feel is very important to me and I like a certain look when I’m over the ball. I like blade putters and I know it when I see it. But if I don’t like the feel of the ball coming off the face, I won’t be able to use it. I’ve been using the same Scotty for over 29 years, a Studio Stainless.

All about feel and sound. Nothing beats that sound off a Scotty sweet spot! Looks come in a distant third hence my Concept X Cx-01 :)