Which proxies to choose
The four lines differ not in quality but in where the address comes from and what a gigabyte costs. Here is where each one fits.
Where the address comes from
Datacenter addresses belong to server facilities. There are many of them, they are fast and cheap, but the network number gives them away — a site that cares recognises them instantly.
Residential addresses belong to home internet providers and are handed to ordinary subscribers. To the site it looks like a person in a city, not a server. Mobile goes further: thousands of subscribers sit behind one carrier address at once, which makes blocking it wholesale expensive.
Premium residential is the same kind with a stricter pool: fewer addresses with a history of abuse, more that have never been flagged anywhere.
Why the prices differ so much
The gap is in what we pay, not in the markup. A gigabyte of residential costs our supplier twice a datacenter one, mobile four times, premium residential ten. Our markup is the same across all four lines, so the price list shows exactly that difference.
Hence the rule: take the cheapest line that does your job. Paying for mobile where datacenter suffices buys you nothing.
Choosing in a minute
The site does not check where the request came from — datacenter. It checks and answers with a captcha — residential. It challenges even a residential address — mobile. You need the cleanest address available and price is secondary — premium residential.
Testing beats guessing: take the smallest volume of the line you suspect and run it against your own targets. The price of a wrong guess at a large volume is not comparable.