Very close. Both have won an Award of Merit so that's not a deal breaker.

In pictures the difference I see is color. Ghio's 'Treasured' has a pinker tint and its beard is orange in the throat ending lavender-tinted white.

Keppel's 'Venetian Glass' looks more milky white with matching beard. Not pure white but less pink than 'Treasured'.

Do you have companion plants in mind?

Companion plants would be nice but I haven't a clue what to put with them. It probably would have to be something that liked good drainage. I have always loved iris but wet clay is no good. If the raised bed does it then I will get more . For now 20 will give me a start. There are only two main nurseries in Canada that sell quality iris . I just drool when I see what one can get from the States. Your photos are an inspiration.

20! That will be a display! Keppel and Ghio both introduce some beauties. Chuck Chapman, maybe in Ontario, also has some nice ones.
http://www.chapmaniris.com/

Sometimes beardeds do not bloom their 1st year. Don't be discouraged.

The two iris are quite similar. Venetian Glass is a bit more blue and little more timid about blooming in my garden in Washington state. I find that Treasured is a very reliable bloomer, which is not always the case for Ghio iris. However, both are quite well done by really great hybridizers.

When you select an iris for your garden, do you mainly do it on the beauty of the plant or the hybridizer? My name and zone isn't showing. Hmmm.

oldrosarian

Oldrosarian, after many years I find I like best the ones I first had a strong initial attraction to. The ones I thought I'd learn to appreciate (it won the Dykes medal, or it's handsome, etc.) never do become favorites.

1. beauty

2. form

3. hybridizer

When having to choose from pictures only, I place emphasis on awards won and the hybridizer.

Also helps if you can see several blooms together. An individual flower may be gorgeous but lacking in a group.

I have a small garden so 40 inch beardeds and very vigorous growers usually are ruled out.

Good advice, especially about the tall ones being very vigorous. Here is my new iris gardens. I will be starting with the plants all around the edges roughly 18 inches spaced. I haven't decided what to plant in the centre. The taller iris?

The smaller raised bed is for the dwarf iris.

Nice!

Didn't mean to imply that every tall bearded is vigorous. Some are, some not. And some of the shorter (34 inches) can be vigorous.

For taller center plants --- tall alliums, delphinium, lupine, nandina (heavenly bamboo), daisy bush like marguerite or euryops, foxglove. I tried columbine and it wasn't to my taste. Mostly I plant in front of the roses.