I've tried Raggtopp. Worked OK, but seemed to lack longevity. That said, I do DD my vert and it sits outside in the FL sun and rain all day. Just applied 303 over the weekend...cheaper than Raggtopp and has better reviews (Autogeek). Too soon to tell, but 1 key difference I like: 303 in a spray bottle (targeted application) - Raggtopp in aerosol (shotgun application).
I also use 303...I was skeptical at first that any product would blacken the top, but WOW! Love the stuff. I use it every 3-4 weeks...takes about 4 minutes to shoot and rub the entire top with this stuff.
When the guys come out to do my carpet in the house every couple months I have them hit the Vert top on the 04 Cobra and the carpets/suede seats too.
They have some 3M scotchgaurd stuff that makes that cloth top look mint. I mean MINT! $20 cash is all it takes as a tip. Lasts 6-7 months lol
I know this sounds stupid. But it works and I have never found anything that works this good to date. They have prof. stuff that was way better than all the other "stuff" I tried.
Well this weekend I used the Mother's to clean and wow! Lots of dirt and grime came out...... After letting it dry overnight I could see the fabric was cleaner, brighter and just looked healthier.
Then I applied the 303 fabric guard. No change in color, and after it dried for 24hrs I tested it. The water beads off nicely....
So I'm super happy. My tan top is now new looking.