Great question - I've been wanting to do a post about this for a while in the "Other Toys" forum.
I have tried every brand you listed - so here are my humble (and not so humble) thoughts on all of them.
- This was the first brand I tried if I remember correctly and I had to send them back due to an allergic reaction (sorta). These smelled great at first - but then it was like there was a chemical aftersmell that gave both my husband and I headaches. I felt like the quality was so-so...the lotions weren't thick - more like Walmart or a drug store quality. I didn't like the way they made my hands feel. Remember though - everyone will have a different experience based on their body chemistry,etc.
was the next brand I tried...and tried...and tried. I find that I keep trying Cake but wind up sending it back - so I can't use it. I wind up with headaches. The top notes of the item usually smell good but the lotions are very very thick and feel "heavy" on my skin. The sugar scrub is nice but feels a bit oily but the sugar is great. I gave it to my daughter - it is probably the one product I could use from the line but the scent is so soft.
I was given the chance to do a descriptive review for Venus bath salts and liked them...but... It seems like it's always that way with Venus products..I like them...but there is something holding me back. Usually it is the fact that while the fragrance is awesome - it doesn't stay on your body. I have the salts in pineapple I think (I gave them to my daughter) and the body butter and spray in peach. The peach smells like a fresh peach and is so yummy...wish the smell lasted more than 5 minutes. I may continue to buy the Venus peach as it is hard to find a true peach smell anywhere else...and there are days I'm in the mood to wear that scent.
I love this line largely due to the scent but the products are great too. I have the ginger/pomegranate scent and it smells like mulled pomegranate or something. My husband has started really picking up on when I'm wearing this and seeking me out in the house...to me it is more of a "winter" fragrance than a summer one. I do find that the scrub is oily feeling (and I think the bath wash too) when you use it - but once you get out of the shower and wipe down your skin, you don't feel oily. This is one of the longest lasting for keeping my skin soft. I started out with one or two products and wound up having to buy pretty much the entire line because I was so impressed.
Not Soap Radio
This was the first line I fell in love with here on Eden (before SS up above). I have most of the products in the Island Hopping scent and a couple of products in another scent. I like the fact that they're not too heavy and the smell is (to me) fantastic. I open the jar of the scrub and feel like I could eat it - it smells so good. In my opinion - this is a great brand. I wouldn't say it is as high quality as say DONA or CAKE or Principessa...but still yet - if you like the scents then you might enjoy it.
I almost forgot this line! To me, this line is closest to the CAKE line as far as heaviness of products and intense fragrance that lingers. While CAKE smells more like food products you'd cook or pineapple/coconut, etc. - Principessa is definitely more of a flowery/powdery - almost what I call a "Victorian flower" scent. The scent is very heavy and will last for hours. Unfortunately, it gave me headaches.
There are a number of products that I LOVE
in the DONA line and a number that I'm so-so about. The key to the DONA line is to remember that when you see "mangosteen" or "acai" or "pomegranate", etc. is that you are not reading what the scent is. You are being told which aphrodisiac has been used in that product. For instance, Camu Camu is a super fruit that is high in vitamin C...but to me it smells like vanilla and coconut (almost a french vanilla with coconut). With DONA, I like the products that are "soap-free" - for instance - the perfume gel, the linen spray, the body butter, the body polish, the body mist lotion. Those give the clearest notes of the fragrance for that line. I find that in the body wash (I forget the exact name - sorry) - I don't care for it as much because of the products in it to help clean. These products are not as heavy as CAKE and Principessa but they are still high quality. The fact that there are six options in each product is great because that gives you a lot of choices. I'm currently playing with mixing products by using Not Soap Radio in the shower and then using DONA to moisturize and perfume my body, etc. I need to keep a journal to note what combinations go well, together! The line does not have a chemical smell to it at all.
One product line you did not mention is Booty Parlor's "Flirty Little Secrets" which is very interesting. My daughter and I both love the smell of the body butter to the point that I had to buy her a jar of her own. Several of the products have a light amount of "glitter" in them and that is interesting to try. I am about to embark on an experiment with some of their firming cream to see how well it works.
I hope this post helps and isn't too long.