They are similar - G19 is slightly longer but the P229 is larger in every other dimension and nearly 50% heavier. This site can be helpful for visual comparisons: handgunhero.com/compare/sig-sauer-p229-nitron-compact-vs-glock-g19

Bob, they are similar sized but the sig 229 is slightly bigger and due to the metal frame is a good bit heavier. If interested here's a link to a sig 2022 Wich is essentially a polymer framed sig 229 and since the frame is made of polymer it's a little lighter and less expensive. Hope this helps, link here................ budsgunshop.com/product_info.php/products_id/14902/sig+sauer+e2022-9-bss+p2022+15+1+9mm+3.9

This is a always a subjective question. We all come in different shapes, sizes and we all have our own likes and dislikes. But for moi I do own about 3 of each (older and newer Gens). The Sig looks bigger, but again looks can be deceiving as it feels smaller to me for me I like the Sig better and do not think they compare much in my opinion I think the P320c is a better match with the 19.
Again it just depends on what YOU think is or feels better. You will never get any real answer online or even by specs of the gus etc. Asking strangers will just get their personal opinions and they don't really count for much as again we are all different. No offense guys. : ) But the best thing would be to visit a local gun shop or range and physically feel and or try each gun. To see how much YOU like or dislike each gun. Remember you are buying and will be using the gun NOT any of us. Good luck and stay safe!

handgunhero.com/compare/sig-sauer-p229-nitron-compact-vs-glock-g19
Length Height Width Weight
P229 Nitron Compact 7.1 in 5.4 in 1.5 in 34.4 oz
G19 7.36 in 5.04 in 1.26 in 23.63 oz

Bob, the Glock 19 will likely be the better carry handgun due to lighter weight.
The P229 Compact specs are Length = 7.1 in - Height = 5.4 in - Width = 1.5 in - Weight = 34.4 oz
The Glock 19 specs are Length = 7.36 in - Height = 5.04 in - Width = 1.26 in - Weight = 23.63 oz
Full details here : handgunhero.com/compare/sig-sauer-p229-nitron-compact-vs-glock-g19