I was looking for a second pair of bibs and noticed a big variation in prices even from the same company. Some are $80 and some $160 and higher.
Why? What are the differences?

The more expensive bibs are better.

Better enough to be worth twice the price?
I have a pair of Black Bibs. They have another pair for exactly twice as much- $40 and $80.

Better material? Better pad? I dunno. I know that my LeCol "Sport" bibs - their cheapest - are great for shorter rides but for longer rides, their Hors Categorie bibs are more comfortable. So I wear those for weekend rides.

Better pad makes sense. I was looking at Primal and they have several in different prices.

The LeCol Hors Categorie bibs are ungodly expensive, but I grabbed 2 pair for 50% off a year or so ago. So now I keep an eye out for sales. Once you find ones you like, buy in bulk. I have enough good bibs to ride every day for a week without repeating. And I don't repeat without washing because, Eww.

Better Lycra, too. Heavier-weight Lycra lasts much longer and provides much better support where it's needed. People who see expensive bibs marked down and spring for a pair sometimes complain that the shoulder straps are too tight when they walk around, but if you love the way heavyweight bibs fit and feel otherwise, it's a minor inconvenience.

More expensive bib have better fabrics and seat pads. What kind of better, well now that depends on the buyer. It's like anything really.

The Black Bibs Ultimate say this :
I've considered buying an Ultimate bib based on the pad shape and design but I'm quite happy with the Sportful LTD bibs I wear. I think the BB Ultimate is worth every penny over the regular ones.

"Worth" is subjective -- meaning that only you can answer that question, since only you know your budget, your mileage, your posterior's tolerance, etc. No one can answer this for you.

But don't delude yourself: in this, as in most markets, the more expensive items are better.

In addition to the pad (which varies in shape, density, construction, and materials; Elastic Interface Technologies are superlative) and to Lycra weight, other factors contributing to cost are the variety of materials used and construction techniques. For example, patterns which use more panels require more complex shaping but allow greater opportunity for materials selection best suited to needs in that area, such as trading off breathability or lightweight for support, insulation, amount and direction of stretch, or durability. Construction techniques can vary the quality and type of stitching and joining, or employ different techniques like seam welding. Detailing, like logo placement, complicates construction adding cost, as do features like pockets and colors selection.

I have one pair of Black Bibs. I like them but I have nothing to compare them to. I am trying to decide between anither one or 2 of them or a Primal.

I've had a couple of the Black Bibs. First was a pair of the Ultimates, after about a year the foam inside chamois disintegrated. I still have a pair of the Ultimate tights/cold weather bibs. My opinion of them is that they are similar to any other $80-100 bib in performance...IMO they're fine for 2 hour rides or longer climb-y rides that I'm out of the saddle a lot. If I'm doing an all-day ride, I'll run one of my $200ish bibs.

As others have said, the chamois pad and the type/lay-up of the materials are the differences between the expensive and cheap bibs. The cheaper bibs use a "open-cell" type foam chamois pad that is often softer. I prefer the firmer pad that usually comes on the more expensive bib.

Most of theirs have a "chamois guide" that makes claims of how long they are comfortable to ride in. How they determine this and how consistent it is with the consumers, I have no idea, especially since saddle model and saddle tilt also play a factor. Also note that their price points don't always align with their chamois levels. I recently bought a pair of Evo 2.0 bibs with their "E6 carbon" chamois rated for 6+ hours, but haven't had the chance to test that claim yet.

Only one way to definitively find out for yourself, pay to play.

This. Get good stuff on sale, rather than mediocre at full price.

BIBS ON SALE

I have experimented a fair bit with bibs at different price levels and in general the more expensive ones are more comfortable and more durable. But fit is also critical and there is a degree of personal preference in things like pad thickness and materials.

Look into the Endura Pro SL line on ebay.
They are MSRP in the $150-$200 range but can be had for $70-$100 if patient.
Love the chamois for long rides and the compression is better than any econo brand.

Since I like my Black Bobs so far I am thinking about buying another pair. I looked on their website and saw they have several other bibs. One I am thinking about is their Black Bibs Ultimate.
Has anyone tried them? Are they noticeably better than the basic Black Bibs?

This question was answered in Post #2, above:

If they weren't "noticeably better," they wouldn't be charging 2x as much money for them. Bear in mind that they are still $80 bibs, though, which means that -- on an absolute scale -- they aren't very good.

I had a brain fart. That was answered. Thanks.

The entry black bibs are very underwhelming to me.
The Ultimate model black bibs are fine, but not nearly as nice as my other bibs- Voler Black Label.


The Voler bib straps go around the side of your pecs. That is nicer placement.
The Voler bibs have more compression, which just feels better and stays in place better.
The Voler bibs have a lower front end which I like for mid-ride stops.
The Voler pad on the Black Label model is thinner, but better feeling overall.

The Voler bibs were 2x the cost of Black Bibs Ultimate and I have never regretted the cost difference. Bibs last long enough that I don't mind the cost difference when it's spread over so long.

I won’t mind buying higher priced bibs after I finish losing weight so I stay at a size. I don’t want to spend $150.00 and them not fit by summer.

I’m on my last pairs of Pearl Izumi, not the cheapest versions, I’ve used them prior. They cheapened the design, removed the edging fabric on the shoulder straps, it’s just flat Lycra. Makes it hard to get the strap to lay flat on your shoulder, now it’s a bunched string of fabric, gets uncomfortable. These were my last pair from PI.

At this stage of my cycling I think Black Bibs Ultimate might be my best choice.

This makes sense. Check that the fit is the same, as sometimes it can vary even within the same brand. But since you like the cheaper version of this brand, the odds are in your favour of liking their more expensive offering. It will probably have a better quality pad and/or materials and construction.