I was originally going to do glass with muntins, but changed my mind at the last minute and went with plain, beveled glass. I'm glad I did. It would have bothered me if the shelves did not line up with the muntins. Our old house has beveled glass in the front door, and we've used beveled glass in mirrors throughout the house, so beveled glass continued that traditional look. I really like it. One more thought. If you are doing glass doors mainly for decorative display, you could do glass shelves and then the fact that they may not line up with the muntins won't be so apparent.

Regarding "lining up"...you can never line shelves up with the horizontal lines of a mullion for everyone or from all points of view. The "lining up" will vary by your height of when you're standing or sitting. If the shelves line up for you, they will not be lined up for someone 4 or 5 inches taller or shorter than you. If they line up when you're standing in front of them, they will not appear lined up when you sit down. So, I would not worry about lining up shelves w/mullions...the better solution is to have glass shelves! As to the yay or nay, I'm a dissenter! I've had my doors w/o glass & the mullions since they were installed. I find I'm not fond of the look of no mullions. However, we have the "prairie" style mullions for when we (someday) put in the glass doors (we do have the glass shelves)...and I'm thinking of getting a different style...one like these from Omega (my cab manufacturer): Source: http://www.omegacab.com/gallery.asp?f=2&pg=16 Source: http://www.omegacab.com/gallery.asp?f=1&pg=41 Source: http://www.omegacab.com/gallery.asp?f=1&pg=44

I just came across this as I'm looking for the mullions. I ordered the cabinet doors (4 of them) prepped for glass, then got the mirrors cut at Lowes (Home D doesn't cut glass or mirrors), which were $20 each. I had to order the clips on Amazon ($8). I'll antique the glass once I find the mullions. I have several emails out to Etsy vendors, O'verlays, and the Art for Everyday for the mullions, but size seems to be the problem, so I may buy a Harbor Freight jig saw and try my hand or find someone with a CNC router. I'd love a CNC router, but new house doesn't have a garage. Sigh! I think something simple like #S742 here https://walzcraft.com/product-category/accent-cabinet-doors/mullion-cabinet-doors/?fwp_paged=2 using MDF is doable. The challenge I think will be matching the color - hoping the antiqued mirror will deflect that a bit. Other thoughts welcome!

I lived in a mid century apartment building and it had unobstructed ribbons of glass around the whole building. Partitions were 'normal' thickness until the window sill then were reduced to 2" thick or so, that way the exterior look was maintained.