I tend to try and take a holistic approach. I spend quite a bit of time checking forums (like here) to see what CPUs are popular, look at trends and compare bench marking.
My desktop CPU history goes: 386DX 25mhz, Pentium 100mhz, Pentium 2 400mhz, AMD XP1800+, AMD Barton 3200, Q6700, i5
[email protected] ghz and now a delidded
[email protected]. I don't really care about vendor and like to think I'm picking the better tech for the right price.
Sometimes I also just make snap decisions. I think I did this with the 7900x... I didn't appreciate the need to delid to run cooler and it def wasn't the bargain option. My PC is for home use, but I also run some of my work sims at home. These apps use multiple cores but are also only certified for Intel CPUs. They would probably run on AMD chips but I needed the results to be comparable to those in the office. I was also more familiar with the Intel motherboard chip sets so all that swayed me.
Btw I'm totally happy with my new 7900X, it's running BF1 and Vermintide2 really well. However if I'd had more time to wait and see how the threadripper chips progressed, looking at their multicore performance I think I might have have gone that way. Seems a no brainer if you want/need that kind of mutil-thread performance for the money.