Good question. The documentation I see is VERY sparse, but the pictures show the same torches.
However, what I gather from these press releases:
http://www.thermadynenewsroom.com/content/view/35/ and
http://www.gawda.org/News_pub/Indust_details.cfm?inID=120is that Victor (under Thermodyne) recently made changes to their product line into a "good", "better", "best" style line, with the differentiation between the lines, being warranty, and accessory cost.
The Professional sets, appear to be cased in stainless toolboxes with 5 year warranties (and come with higher quality grade T hoses, and steel regulator gauge guards), the CutSkill in plastic toolboxes with 2 year warranties, and the Firepower in blow molded cases also with 2 year warranties.
So, with that understanding, the Professional line 315FC, CutSkill WH 370FC-V, and the Firepower WH 370FC-FC appear to be exactly the same torch (with different warranties).
And in your question, the Professional line 100FC, CutSkill WH 270FC-V, and Firepower WH 370FC-FS, also appear to be exactly the same torch.
So, the price difference in the kits, is probably because of the different cost of accessories, and the warranty, but the torches are the same (and who would mess with something as good as this)
Also new, are the HD310C torch, which is compatible with the 315FC, but is cheaper, because it comes without the flashback arrestors (so avoid this),
and the H315FC, which is a revamped 315FC designed for high flow rates (too big for me, but looks VERY nice).
Anyway, they're all a great choice. I do everything with my 100FC, and hardly ever reach for the 315FC. In fact, I only have the 315FC, because I noticed an auction on eBay, listing 50 feet of old cracked welding hose, with an old torch attached (which I recognized), and paid a song for the hose, which I promptly threw out. :) I will say, that if you're welding or brazing often with tips larger than Victor size 2, the longer handle of the 300 series, is more comfortable, from the extra heat. Most of my work is with the 00, or 0, and every so often the 1 for larger things, so the 100 series is great.
-- Robert