I've been a long time user of both NailTek Foundation and OPI Nail Envy as basecoats and I always get a lot of questions about how I maintain my nails so long without breaking. I have a separate article on that with some tips, but I also think the right basecoat and topcoat make all the difference.
I started out using OPI Nail Envy (Original Formula) and used that for several months. At first I thought it worked great as my nails were definitely getting stronger and therefore longer as there was less breakage. But I also noticed my nails were still peeling a lot, where the top of the nail would peel into its various layers. This meant I had to keep buffing them to smooth out the texture, which resulted in weak and bendy nails, and therefore caused breakage.
so check their website and make sure to select the one right for you. I have noticed major results as my nails don't peel at all anymore - they are strong and healthy. I also think using a glass or crystal nail file instead of those cheap emery boards has made a huge difference. For topcoat I still swear by Seche Vite.
Overall I can say that this product worked wonders for my own nails. It has a very strange and unpalatable smell, but I can overlook that. This product leaves a "grabby" matte texture on the nails that color polish sticks to really well, versus the OPI Nail Envy which felt and behaved just like a clear glossy nailpolish. I definitely noticed more pulling when I used Nail Envy, meaning there would be slight bald patches on the nail where the application did not stick on smoothly. NailTek Foundation smoothes out my nails and helps my polish to adhere; in combination with Seche Vite topcoat, my manicure easily lasts for 5 days, depending on the polish I use.
I order my NailTek from transdesign.com but it is also available at other e-tailers and salons.