Oh my.
I am a FO HO in recovery. I have tested (either OOB or in soap) over 400 FOs. I didn't buy all of these! Some I exchanged with other soapers (we traded vials or gave each other FOs we didn't like). I also was in a FO round robin in which a box went around the country - each participant took out what she wanted and substituted with a like quantity of FO she didn't want. Most of these FOs I got in sample vials or one ounce samplers. If you have no interest in curing a FO addiction, I recommend AHRE's and Peak Candle's sampler sales which they run periodically!
The reason that I am in recovery is that I liked, at best, 20% of the FOs, and I have switched to EOs which I vastly prefer. I also did extensive research at the wonderful Soap Scent Review Board in order to select FOs that would do best in CP soap. So in theory, I had weeded out FOs that seize or fade or morph.
Vendors I have tried: Adobe Soap Words, Aroma Haven/Rustic Escentuals (AHRE), Bramble Berry, Bitter Creek North, Nature's Garden, Camden Grey, New Directions Aromatics, Elements Bath & Body, Majestic Mountain Sage, Oregon Trail, Peak Candle, Southern Garden Scents, Daystar, Southern Soapers (now Soapalooza), Wholesale Supplies Plus, Candle Science and The Scent Works.
General impressions (everybody's nose is different so this is entirely subjective). I don't like foodie scents. I tend to prefer fruits, florals, woods and spices and generally single note or simpler blends. So perfume dupes tend not to work for me either. I also don't like powdery scents.
Every vendor will have some standouts and some duds. However, some vendors seem to offer better quality across their entire line than others. This is not always related to price. For example, two of my favorite suppliers are Peak Candle and AHRE. I have not had such good luck with Nature's Garden (also inexpensive) but others have.
Rather than go through 441 fragrance notes, let me summarize:
Coconut: most were plasticky or weird. Peak Coconut Milk for me was the best in a line of bad contenders.
Vanilla: also a lot of bad ones out there. Day Star Vaniglia de Madagascar and Soapalooza Bourbon de Vanilla are my favorites
Honey: I have discovered that honey FOs have a component that makes me feel physically ill. I can smell whatever it is through the bottle. So those 8 ounces of Honey Bee from Southern Soapers/Soapalooza was a definite regret.
Pink Sugar: I don't understand the hype over this one. It smells sickly sweet and turns dark, dark, brown. I tried three different versions before giving up. A big regret.
Variations on Black Vetiver Cafe and Green Irish Tweed - don't like either; the latter smells like Irish Spring to me.
Ozone scents: never could find one that smelled truly like the ocean or air after a rain storm. OT's Mediterranean Sea Salt comes close but has a hint of floral. Very nice but not the true scent I sought.
Apple: tried half a dozen and couldn't find one that didn't smell like a Jolly Rancher or morphed into a weird bitter note in CP. Soapalooza's Island Pear could pass for apple.
Fruit scents: Peak, Oregon Trail, and AHRE seem to do pretty well in this category. I find that tropical fruits, citruses, and raspberry/blackberry are relatively easy to find good ones. Apple, pear, strawberry, grape, watermelon, not so much.
Florals: Peak and BB do pretty well in this category as does TSW. I've heard Sweet Cakes does as well but I never bought from them because they are relatively expensive.
Pumpkin/Pumpkin Pie: I've tried many and most smell fine and pretty much the same - clove and cinnamon dominate. To me, BB's Pumpkin Lager smells most like pumpkin as opposed to spice. NDA's is great OOB but loses its complexity in CP.
This is already longer than I wanted it to be. Conclusion. Sign up for the Soap Scent Review Board:
http://soapscentreview.obisoap.ca/ Do your research, and then hope for the best.
My subjective experience: The Scent Works, Soapalooza, Brambleberry, and Oregon Trail have quality fragrances and are pretty reliable. Less expensive and also good are AHRE and Peak Candle. NDA is terrific for EO but I wasn't too impressed with the small sample of FOs I tried from them. AHRE and Peak ship very quickly; Brambleberry and OT can be slow. TSW is prompt unless they're having a sale and then they can get backed up. I haven't bought from Soapalooza since sales reverted to Kelly Bloom (founder of Southern Soapers who developed these fragrances) so I have no experience with her customer service. I have liked some WSP fragrances but they have become quite expensive.