So I ended up ordering the V4 and Optima while the sale was still going. I figured with the cost of shipping and all I might as well do it at the same time. If I didn’t like one, I could always sell it. So this review will focus on comparing the two. This will be more useful to others as I am new to the whistle and have nothing for comparison other than a Generation, and Clarke High D.
I played the red top Optima exclusively for about 5 days. I put a lot of playing time into it, and my family was very patient.
Scale after scale after scale. The fingering was harder than expected. I have big hands, so I didn’t think it would be a big deal. But, it was the stretch between hole 5-6 that was difficult. I never realized that hole 5 may not be evenly centered. I had a vice grip the first evening, but it soon relaxed and scales became much easier. The first thing I noted was that low D (when fingered correctly) was loud. This is a different experience than my Clarke D. Volume was not much different than E. I find the Optima to be very forgiving. Low D is a little finicky on breath requirement, but as you move up its pretty forgiving. The has a nice bell tone to it with a bit of raspiness. The bell tone is not pure as there is some breathiness to it. I'm sure there are correct terms for all this 
. It is a very nice balance. I think this whistle shines in the second octave. Having a forgiving whistle, you can underblow and overblow to create a nice range of tones within the same note. I especially like the chiff when overblowing. In the right hands this could be used for a lot of expression. Around A on the second octave, the wind requirement picks up. The last two notes sound a little flat, but to be honest I think a lot of that is me. I don’t spend much time practicing there due to volume and I’m not in the habit of blowing hard enough. If you’ve seen Phil’s video https://youtu.be/lZHBCpU3BVs it is a pretty good representation of what it sounds like… except better playing.After picking up the V4 it was immediately noticeable that it was easier to play. The fingering was bunched a little closer on holes 1-3 and hole 4 was more centered. This allows me to go between F# to D with greater ease. It’s easy to miss hole 4 when the spacing isn’t centered. Low D is easier to hit as well. The first octave is very balanced with breath requirement, and it isn’t until around G or A in the second octave that the wind requirement really picks up. There is more back pressure on this whistle and I haven’t got the knack for the upper end of the second octave yet. Overall the whistle is quieter than the Optima and gets a lot of play time because of it. The sound of this whistle is very smooth. I picked a few notes while listening to this https://youtu.be/PJnR3vsTkKs and it has that same smooth sound. I’m sure there are differences in sound, and I certainly can’t play this song but hopefully you get the idea.
All in all, I’m happy with both whistles. The build quality on both is very high. The Optima did not in any way look or feel like a toy (despite the cool fire engine red top). I think the Optima is the most versatile of the two, but the V4 is great for playing when you need lower volume or after that smooth tone. The V4 easier to play better in the hands of a beginner (at least my hands). Also I think this would be a great whistle for recording. I'm sure it can be used to play with others as you can get volume out of it, but there will be limits as to what instruments and how many. It probably won't cut through the mix with too many instruments unless mic'd. For me it will probably only be one other guitar, so I doubt it will be an issue. It will be interesting to see where my thoughts fall on both of these a time goes on, but I don’t see myself selling either any time soon. I hope that you find this comparison useful.
