See Language required for citizenship - GV
Several forum members have completed their online PLA course with Edpro.
The NIALP course sounds exactly like a PLA course if you look at their description.
PLA is not the same as A2, though both certificates are valid for naturalisation.
A2: The advantage is that you study at your own pace. When ready, register for the CIPLE A2 exam, pass exam, get certificate. The disadvantage is that the listening section of the exam is notoriously difficult, exam slots are hard to get outside Portugal, and many people have exam phobia.
PLA: The advantage is that you don’t need to give a big fat public exam, practically everyone passes and gets a certificate, it’s largely based on your regular attendance in class, small tests, interactions during classes. The disadvantage is that the schedule is intensive - you need to set aside 4 hours per day for about 8-10 weeks (4-5 days per week), and you can’t skip too many classes, need webcam on, can’t multitask during class, etc.