I've been with Skinny which I understand is Spark network for 3 years now using an android smart phone.
I have their highest plan $46/mo.

I can say without a doubt in the last 1 year the performance for data apps has degaded noticeably on every single app that I use. Email, Social media etc.

I also noticed calls dropping, reception being low or weak constantly and this is something that has gotten worse over time.

I am getting the feeling that Skinny network is simply overloaded.

Does anyone know which network is currently offering the best performance?
I am considering a switch to 2Degrees but have not decided anything yet.

Based in Auckland Central City so do not need rural coverage.