I couldn't find a thread for this exact string. I am confirmed Spirocore user. I have also liked Correli's. Spiros have just become so expensive and not as simple to find. Right not I prefer Spirocore solos. The bass shop I use was out of them, but had a set of Helicore solos that were given to them, and gave them to me. I only needed the D/E, but was curious about a brand new full set and free is great price! Review after a week of breaking in: They are a VERY solid hybrid option - super sweet with the bow, a nice full growl/bloom and crisp pizzicato sound which is surprising. There is less top end, "arco string" means they dampen the harmonics somehow. Pizzicato harmonics are not super great, but that is pretty much my sole complaint so far. They may open up in time. My first two gigs with them will be the next two days so I'll report back. They are REALLY nice arco. For the price and availability Helicores have always been a decent option, I have had Low Bs on my electric uprights that I have never bothered to replace. The end verdict: I'd take them off for a free set of Spiro solos, but wouldn't bother to upgrade already having them. Kind of like the mp3/cd/Lp fidelity couch-test: If I have the mp3 of an album, I won't get out of my arm chair to find and put on the CD, I will however, often get up for the LP.