Personally growing 20+ cultivars at the grove, and they all vary drastically. Some are highly acid and others are not, some have thicker skins and slight color differences. They come in all shapes. Taxonomy is very tough on guavas.
‘Bogor’ Indonesian is claimed to be highly fruit fly resistant by some experts.
There’s a few white common guavas that are excellent, not the Thai white.
Commercially known as cv. ‘Homestead’ which is a hand polinated cross by George Ruehle of ‘Ruby’ x ‘Supreme’ is another common one.
There’s a lot of variants that are ok, mainly from seedlings, and most importantly taxonomy on guava is quite tough. You may not know what you have or are being sold. So, the best way to get something good is via vegetative propagation of a tree you know is great, for your preference of taste.
I think mixing various cultivars for jams, smoothies, cooking purposes etc. produces a much more rounded out guava flavor that is delicious and highly nutritious, much more than other fruits. Potassium, Lycopene in the skin, more Vitamin C than oranges. By mixing cultivars you create a flavor you can’t acheive with 1 tree. Consider it like blending various mango cultivars for culinary purposes.
