The R063s are a mixed bag of good and bad. The glass ﬁbre reinforced sole is curved to provide comfort and offers good stiffness and low weight.
However, at the ﬁrst sign of either of the two straps being tightened, the lack of a tongue means that your feet are subjected to various pinches, rubs and probings from the unpadded upper.
For hot summer days or triathlons the large sole vent at the toe would be great, especially with the extra aeration from the large mesh panels. While undoubtedly cheap, the ﬁnancial saving might not be worth the loss of comfort.