I would rank the kits that I have made in this order:
1. Cellar Craft. I have used both their Showcase collection (reds) and their Premium collection (whites) and found both to be excellent. I have ordered the limited release Sangiovese/Cabernet Sauvignon and I am eager to see how the Vineco acquition has affected the product.
2. RJ Spagnols. Their Winery Series never disappoints.
3. Wine Expert. Only for their very high end kits.
4. Mosti Mondiale. Only for whites. I have been disappointed in their reds all the way up to and including the All Juice Masters Edition. I have not tried the Meglioli because there are less costly and excellent alternatives.
These are the only kits that I have made and I understand that some people would disagree with my assessment of Mosti Mondiale. I am not sure what my problem is, maybe not enough talent or maybe not letting them age long enough. I suspect that I am doing something wrong because several very talented winemakers on the forum, e.g. tonyt and cpfan, seem to get more out of the reds than I do.
I would also add that most of my latest and best wines are from buckets of juice (L'Uva Bella and Mosto Bello) augmented by the addition of a grape pack, which I purchase on line.