Segotep, while well known brand in China, is mostly unknown brand in the rest of the world and in PSU community as well.
I couldn't find any reputable reviews of the two Segoteop units you mentioned and here, i'd avoid Segotep PSUs. Without reputable review, it's impossible to tell how good build quality those PSUs have. Also, PSU's efficiency (80+ Platinum, 80+ Titanium) has little to nothing to do with PSU's build quality.
Power supplies are guilty until proven innocent; you need reasons to buy a PSU, not reasons to reject a PSU.
Only official info about GP600T which i found was on the Segotep webpage and news article where they upgraded the GP600T warranty from 3 years to 7 years,
link:
https://en.segotep.com/news_show.aspx?id=6
For comparison: Seasonic, one of the oldest and best PSU OEMs in the world; when they released their PRIME series 80+ Titanium PSU, Seasonic gave the PSU 10 years of warranty and not 3 years, like Segotep did. After some time, Seasonic also upgraded PRIME series PSUs warranty but within reason and they added 2 years. At current date, Seasonic is the only PSU OEM/brand in the world who offers
12 years of warranty for their flagship PRIME series PSUs. Also, Seasonic PRIME series PSUs are the best PSUs in the world money can buy.
That being said, i suggest that you look towards any Seasonic PSU in 600W range. You don't have to go with the PRIME series, Seasonic also offers more wallet friendly Focus and Focus+ series. Even the older Seasonic units: S12II series, M12II EVO series, S12G series, G-series, X-series are good quality PSUs,
pcpp:
https://uk.pcpartpicker.com/products/compare/nB3RsY,Tc3RsY,qZKhP6,WrNypg/
Warranty wise:
S12II: 5 years
M12II EVO: 5 years
Focus+: 10 years
PRIME: 12 years (includes all PRIME models: regular, Fanless, AirTouch, SnowSilent, Ultra)
All my 3 PCs: Skylake, Haswell and AMD are also powered by Seasonic. Full specs with pics in my sig.