They are much easier to shuffle although I still riffle them, sideways.
When I trim a deck I use my large scissors because I want each cut to be a whole, not several snips, too easy to get jags that way.
When I did my first deck I practiced on a deck of casino giveaway cards first, just to get the feel and where the scissors edge would fall on a line.
I always cut the short ends first, then the long sides because that leaves shorter long sides, less chance of getting off the line.
It takes me about 2 hours to trim and do the corners on a deck, and while doing it I learn more things about a deck because I'm looking at each card 8 times from 4 different sides.
Very valuable in my book.
I got my corner rounder at Michaels crafts, all craft stores and scrapbooking stores have them. I practiced with it on my freebie deck too
You can get the corner lodged in crooked but another try perfects it up.