__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
Gonna go with FOTJ era. Some of, not arguably, the most powerful force users ever in Luke Skywalker and Abeloth. Then you have other, lesser powers like Caedus, Kyp, Krayt etc.
__________________ "You must begin by gaining power over yourself; then another; then a group, an order, a world, a species, a group of species... finally, the galaxy itself."
- Darth Plagueis
"She may be small but she packs a punch and when shes in this mood...she goes for my danglers" - Oghren, Dragon Age
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."
What, KotoR? Where they talk about how great Ancient Sith were in comparison to them? It has some badasses, but I don't think it's even in the running. There's a relatively small handful of major forceusers that we know, and while they have some badasses, they aren't even in contention with any in the top tier.
SWTOR certainly does have a whole ton of powerful Jedi and Sith, having both the largest Jedi order ever and the largest Sith order ever to recruit from.
And CW era, also known as the Golden Age of the Jedi, you have a large well-trained Jedi order with a good number of high-potential people, who the war helped sharpen. Includes a few of the strongest Jedi of all time.
FOTJ era certainly has a lot of powerhouses, though not as many total as TOR. The inclusion of multiple fully-trained Skywalker blood people, plus a couple other significant badasses, certainly puts them up there. Though the total size of the era is small- under 1k Jedi, very few Sith.
KotOR was called a Golden Age of the Jedi, even more so than the PT.
Anyway, it depends on what the OP was asking. If he is wondering which has the best average force users it's undoubtedly NJO due to the smaller amount of Jedi compared to other eras and vast amounts of powerhouses.
SWTOR without question, due to the sheer number of powerful Sith. The Jedi, meh. They have a handful of very good ones and a couple of top tier, but the Sith are the ones who make the era stand out above the rest.
I can't say PT mainly because there were very few Sith, but it comes as a close second because it does host some of the most powerful Jedi and a couple of the most powerful Sith in the mythos.
__________________ There's a man goin' 'round takin' names.
An' he decides who to free and who to blame.
Everybody won't be treated all the same.
There'll be a golden ladder reaching down.
When the man comes around.
The PT Jedi were more numerous, the top end of their lineup was downright scary- Yoda, Anakin, Windu, Kenobi- plus they had a rather impressive rack of not-quite-that-badass-but-still-pretty-badass-masters, both in and out of the council.
Plus the Sith of the time, while few in number, were in turn quite good. Sidious, Dooku, Maul, and eventually Vader. Toss in Savage and Asajj for two strong understudies as well.
Well, problem- while you have 'etc.' at the end of your list, that's pretty much it for the powerhouses! There's a few other skilled but not as strong masters, and then the list ends.
And the Exar Kun war did such a number on them that they started having problems like the Jedi Covenant's sith paranoia, and fear of many Jedi to act in non-sith related things.
By the time of the games, they only had two sith of real power, Revan and Malak (plus Traya, but she was not out and active til those two fell), and the Jedi relied on numbers when they tried to hit Revan. Another powerful Jedi (aside from Revan) didn't really arise until Meetra.
It does seem to be an era with strong powerhouses and a thinner average cast. I guess that's just what I was getting at, Thon and Nomi have been compared to Yoda ( or vice versa ), and I feel like the strongest Jedi from that era were definitively some of the strongest ever.
My issue is that the Swtor era has a similar caliber of big name Jedi and Sith but far larger numbers and superior quality of the average rank and file, compared to the previous era's.
The Sith are evolved versions of the Golden Age guys, with much greater martial focus and better training. And the Jedi are evolved Kotor Jedi who possess the same knowledge as before but have rediscovered lost secrets that have improved their training and they've geared much more towards war by using armor and other gear.