This is all quite confusing for me. What's the difference between pps and EI dosing? What do you personally dose?
PPS and PPS-pro are based on daily dosing of much leaner amounts of nutrients. EI is based on dosing much larger amounts on alternating days. EI doses macros (NPK) and micros (CSM+B) on separate days, so your EI dosing would be something like macros on M-W-F, micros T-Th-Sat, 50% water change Sunday.
Since you're new, I'd highly recommend you start with the EI method. With PPS, if you run too lean and don't know what a deficiency looks like yet, you're going to have problems. EI, in theory, provides adequate or excess amounts of everything your plants need throughout the week, but requires the weekly large water change to "reset" the water column. You'll very likely still have accumulation, meaning your NO3, for example, will gradually increase over the weeks, so occasional testing to make sure your numbers aren't getting out of whack is a good idea. If you need to cut something back, you just dose less or skip the dose altogether.
I've purchased from both NilocG and GLA. I, too, like the jars, so my initial purchase is for the jars, then I just refill from bags as I need to since the jars add a little cost.