That's a fair statement. My standard for this type of show remains BBC's Tinker Tailor Solider Spy (1979) and the follow up Smiley's People (1982).
Alec Guinness owns Smiley. Just perfect. Absolutely gripping yet low budget [+] it actually demands that you use your intellect to keep up. If you haven't seen those I say whip up ye old torrent client and get some.
Anyways, I did say "too greatly". Someone up there says "no spoilers" so ..