Everyone here seems to be averse to buckles, but I can tell you the biggest luxury to me is a waist and leg loops I can open. This drives the price point, and to an extent, the weight of a harness up. It is not a requirement, but man it's nice.
If you're using it as a backup to some sort of sling, and weight is your biggest concern, you've got several of the ultralight harnesses to choose from. These usually don't have leg adjustments, but a couple do. None will have buckles. They are comfortable enough for climbing/rapelling 20-30'. They get more comfortable over winter clothing - this is important when choosing a harness. If you're hunting in really cold temps most of the year, a padded more comfortable harness is kind of a waste. Keep in mind, You will be stepping into them. Another tip is to put them on over base layer, and leave fly's open to clip into biner as you layer up. I've done it with two layers.
If it's something you'll use a lot outside of your sling - setting cameras, setting trees/platforms, any other climbing (hell i'm the neighborhood limb cutter now, be careful who sees you climbing in your front yard), I'd recommend getting one of the more comfortable padded harnesses. You're still going to be stepping into these. But they'll be more comfortable with less clothing. Tip here - they're going to have all kinds of gear loop and extra crap you don't need. Look for a more minimal one.
I have these:
https://www.amazon.com/gp/product/B01NGZ3OVQ/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Lightest weight - looks like a piece of lingerie, but does the job and packs up size of my fist. I actually removed the keeper straps for the leg loops. This allows me to sort of step into it. I essentially bring the waist loops around, clip into a biner, then reach between my legs and pull the two leg loops up and do the same. It weighs nothing, and make sure you're wearing briefs and adjust before you load this thing up...
https://www.amazon.com/gp/product/B01K5P53KG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Just picked this one up. weighs 19 ounces. The metal buckles are heavy - I assume in the effort to make it cheap, they forego aluminum for steel. But, this is pretty comfortable, and has no extra bells and whistles. One gear loop on right side. Honestly, if this thing had aluminum adjusters, it would be perfect for what i'm doing.
https://www.amazon.com/dp/B00ZR7BVUE/ref=twister_B001V7UU24
This one weighs 15 ounces. I cut all the extra gear loops off the back - they interfere with slings. It's comfortable enough with the padding. I've had it for 2 years now and will probably switch to the one above this year for the majority of my uses. I don't really feel a huge difference in comfort in the two for our purposes, and the other one has less going on, in spite of the extra weight.
http://saddlehunter.com/community/index.php?threads/new-option-for-saddle.3715/
Then, you can see my homemade sling I made - load rated buckles on waist and legs. Being able to click on is a huge advantage.
https://mistymountain.com/shop/military-tactical/military-harnesses/ish-ultralight-urban-sit-kit/
I'll be making a copy of this myself. The buckles are about 75.00, and I'll spend another 15.00 on the webbing and several hours hand stitching the load bearing joints. Honestly for what we do - this is the most convenient option available, but it comes at a price.