I've taken a quick look at the website, there's a lot of material, very interesting.
I don't think it 's about bashing Tektronix. It's on the contrary rather candid comments about test equipment from various brands.
Nothing is perfect, every design has shortcomings.
In particular, the guy explicitly recommends Tektronix for scopes (and HP for spectrum analyzer).
And he notes that most Tek problems are mechanical, whereas HP is electrical.
I wouldn't view that as "berating" Tektronix, that's rather "positive" for a company selling electronics.
I've included below an excerpt about fixing 7000 series scope plug-ins (see "Tektronix 7A12, 7A13 (new & old)").
"Rather than describe all the fixes, I'll summarize. The same comments apply for the other Tek plug-ins listed on the page. Very simply: Tektronix problems = mechanical, HP problems = electrical. I've learned this theorem over several years. Part of Tek's problem was their propensity to socket everything, including transistors. Then there's the cam switches. You can fix 90% of the 7000-series plug-ins by reseating everything in a socket and disassembling and cleaning the cam switches. The remaining 10% are switches, pots, tantalums, light bulbs, etc."