IMHO I recommend taking the class to be more focused on it if you take the on-demand will take you longer to finish it.
INMO, Class room training are best if you have existing knowledge on how VMware Virtualization works.
if you are totally new to the VMware concepts then 5 days will be too much of load to grasp the concepts...
1. Try classroom training for good collaboration with the people and if you are quick learner it can help you.
2. On demand classes can be considered if you are ready to spend sometime to learn the concepts slowly and gradually you will grasp the concepts ..
also please check - Try VMware NSX Hands on Lab for Free | VMware
all the best for your future!!
VMware is an amazing technology and you can learn as long as you have the hunger to learn all the best routing1000
Ive done the NSX-T ICM on demand training and it was actually really good! Usually i would say go classroom if you can afford it but frankly the online course was well worth doing and was very engaging. More so that some others i had completed which felt painfully slow
Combined with some HoL & Home Labbing, it should be more than sufficient to get you going with NSX-T