Pears as your aware get very large if grafting on seedling rootstock or grown from seeds. From my perspective an Espalier system wastes some wood and fruit considering the space they take to grow. Here is a video on youtube showing the size of a large pear I will use as an example PEAR TREE BIGGEST EVER - YouTube. Stephen Hayes shows in this video an espalier system Summer pruning of espalier pear trees - YouTube which I wanted to post since he does a great job growing fruit. So my thoughts are every year at least twice a year in an Espalier system we’d prune off extra wood. I don’t see the benefit to that unless of course you don’t like to climb ladders and then i understand. Is there ever a situation where a pear tree that grows straight up 30 feet and has a width of 10 feet every produces less than an Espalier system that is 10 feet? It seems to me like the system wastes a lot of wood and pears with no reward accept more work. What am I missing? There is something very majestic about a really big pear tree like this Perry pear tree Harvesting Perry cider pears.Part 1 - YouTube and Harvesting Perry cider pears.Part 2 - YouTube
The adavantages of espaliered pears are: bringing them into production quickly, ease of maintenance and harvesting. I personally like the esthetics of espalier trees.
Yes your espalier trees are beautiful. I’m trying to justify the need for some or talk myself out of ever trying them. The large pear trees work nice here.
I like your picture…with the wedge of geese…!!
For someone who has lots of room and doesn’t mind getting on a ladder I’m not sure there would be appreciable benefits. In my small yard, they let me pack extra trees in. Plus I think they are beautiful (as would be a large tree!). From what I understand they were originally grown in monasteries and also took advantage of the microclimate created by growing the trees against the heavy stone walls giving you frost protection.
Thanks for linking that video from Stephen Hayes, Clark. As somebody who’s trying to get an espalier started this spring, I found it very helpful.
Another advantage high is that a high vigor rootstock that dose not need irrigation can be used. Pears seem to thrive in restricted forms and once they change from vegetative growth to fruit buds they can be pruned once or twice a year. On free standing trees, I see spur bound high productivity branches break under fruit load and cycle back to vegetative growth. With some support, you control the balance of fruit spurs / new growth.
On the same topic of espalier… Is it possible to actually grow (and harvest fruit from) an espalier fruit tree against a brick wall in my climate (USDA 4, north-eastern temp fluctuations, etc…) ?
South facing wall = too hot in winter, would kill fruit buds…
West facing wall = almost as hot as South facing wall…
East facing wall = winter morning sun = the worst ? Also not enough sun to develop sufficient sweetness in most fruits…
North facing wall = not enough sun (almost none) to ripen the fruits
I am thinking about asian/russian/euro pear, Mirabelle or Italian plum, Golden nugget apples…
My plan: Korean Giant asian pear on a west facing wall. Is it crazy??
Im going to be trying a KG on a SE facing wall 
guess we will find out!!
Jessica,
KG is a late ripening pear in my zone 6a. It can be harvested starting in mid Oct. This past year, I let the fruit hang until some time in Nov.
I wonder if you would be better off planting an early ripening varieties. Shinseiki is good tasting and a mid season variety.
Thanks Mamuang. I have Shinseiki et I like it very much. I tought an espalier against a wall might give me a chance at ripening later varieties, but I might be pushing my luck with KG. Thanks for the suggestion!!! 
I agree with @mamuang because my experience has been the same with it being pretty cold by the time i harvest Korean Giant. Kansas a slightly hotter 6a than most and we tend to ripen everything fast. Duchess D’ Angoulme is a later ripening European pear and KG hangs long past it here.