无论“ 是 regardless In this sentence ”这套沙发无论样式，质地，还是做工都挺不错“ it is still means regardless. The key word in this sentence is the workmanship. Simply means, in regardless what so ever, the workmanship is good.

“无论”可以这样子用的，这样的用法很正常。就比如说“这个款式和质量都很好”也可以说成“无论是款式还是质量都很好” 不论，不管no matter what 是“无论”现在最常用的意思。它还有的意思是 更不用说don't say 和 不追究

I think 无论 is a conjunction in Chinese, which means despite what kind of condition. While regardless exists as a adverb (at least, google online dictionary tells me that). So they fairly have difference. And regardless also means ignore there or those terms. 样式，质地，还是做工, tries to express a condition in this sentence, which means in terms of pattern, quality. 论 in this case means refer to, while 无 means despite. Then 无论 means no matter how the point you refer to, it will ..... er...... mybe my answer can't help or not.

无论means 'regardless of', that's for sure. But in this case, it's better to understand it as 'no matter what/how'. 无论A还是B都...... Such structure is often used, and it is to emphasis A and B. It's kind of llike 'not only...but also...' By the way, you may understand 质地 as quality, but that's not precise. 质地is more about the surface of something, how you feel when touching it. So, I think 'texture' is a better word for it. Hope it helps.

用字詞取代法: 這套沙發「不管是」樣式、質地、「或是」做工都挺不錯。 表示逐一點數各種性質或狀況。