Tau 7 is better than Tau 8.
The Tau 8 is Tau's first attempt of a PCP pistol. It has several flaws, as had its mk300
I have 1, both the mk8 and mk300.
Without even shooting > 50 shots, the mk300 has seals changed because they were damaged.
Probably damaged from factory because of their finish
The mk8 probably has the same issue. Hadnt sent that 1 back to Tau though.
The mk8 ónly shoots well with 1 pellet
Also, I had to up the front sight, cause it shot way to high
Availability of all grip sizes and finishes is limited.
They're heavy too, in standard version.
They loose air when the cilinder is left attached.(even when not attached but much slower)
They do let you feel the air blow away on yr hand. Still not sure wether thats the airstripper (which is large) or some pelletprobe leak.

That said, they're awesome to shoot, very recoilless. Trigger feels almost like an E trigger. Very clinical.

I've had it a few years now, maybe the recent one's have all this fixed and updated.
But the Tau 7 has been made for about 40 yrs now.

Other starter pcp's:
Alfa Proj/AA: dont do it only good in co2 trim
Aeron Spider : mine has been back to factory under guarantee twíce although very nice pistols to shoot.

So if yr considering pcp, buy a sechand steyr/walther/fwb/morini and have that serviced. Best buy
Love my morini 162E