In absorbing people's opinions here, bear in mind a few points.
1) RV-8s tend to be nose heavy. Putting battery and some avionics in the back, and a composite C/S prop are a necessity. With those done, an angle-valve equipped -8 can get the c.g. in about the same place as a parallel valve equipped one with a metal C/S prop. Flying an RV-8 that is nose heavy really is noticeably less 'nice'.
2) RV-7s tend to be tail heavy. Putting an angle-valve engine on would be a good way to expand your useful cross country baggage-carrying capability, and handling will be fine, since the c.g. will still be in a very good location. Flying an RV-7 with an angle-valve engine is not going to be quite as responsive, but it is plenty responsive enough to be really nice, and will be more broadly mission-capable. More baggage without hitting aft c.g. limit, better high-altitude ops for mountains, high desert.
3) Although it is true that angle-valve 360s really only make max 195 hp, that is still more than a parallel valve 360 will do with stock compression ratio, even if ported/polished, etc. Yes, a PV engine can get souped up to 195 or more hp with increased compression ratio, but there are other ramifications to that choice. This partially negates the perceived benefit of more readily available, lower-cost parts. I would be comfortable running a CR 8.7:1 angle-valve on UL94 fuel, but NOT a CR 10:1 parallel valve engine.
4) The bigger benefit from the angle-valve design is not the max Hp, it is the better breathing so that WOT operations at cruise RPM and cruise altitude DOES yield significant horsepower improvement compared to the parallel valve engine. The performance difference at high density altitude is VERY noticeable. A horizontal cold-air induction/sump on a parallel valve engine would get some of this same benefit, but it is an expensive add-on that offsets some of the cost differential between the AV and PV.
5) The angle-valve engines extract a lot of their heat thru piston oil squirters, so the cylinders run nice and cool (and last a looooooong time) but the oil gets really hot unless you put significant effort into designing a good oil cooling system. Plan ahead to install a large cooler on the firewall, supply it with lots of air with minimal pressure loss (lots of threads here on VAF about doing that).