The phrase 'are of comparable quality' is correct and usable in written English.
It can be used to describe a situation in which two items have the same standard of quality, or are close in quality. For example: "The two brands of paintbrushes are of comparable quality, so choosing one is purely a matter of preference."
Regarding the SURtc vs. K m correlation, the current results are of comparable quality to that observed in [1] (R 2=0.92 compared to R 2=0.96), where the correlation of SUR and K m as derived from Patlak analysis of dynamic studies up to 60 min p.i. was investigated (see Figure 4 in [1]).
Many of the diamonds sold by jewelers on 47th Street are of comparable quality to those at Fifth Avenue salons like Tiffany & Company or Cartier.
We evaluated whether self-reported comorbidity and register-based comorbidity are of comparable quality.
Inclusion/exclusion criteria for the search are designed to insure that primary studies are of comparable quality.
Some generics may well be of poor quality - a fact that brand name pharmaceutical companies are keen to point out - but many generics are of comparable quality with their 'brand name' counterparts (Newton et al. 2011).
Therefore, findings in this report are of comparable quality.
Thus, the vegetables grown with BBRDM and DAP were of comparable quality.
The proposed algorithm is of comparable quality to traditional sequential counterpart on central processing unit (CPU).
The authors noted antenna (line-of-sight) images were of comparable quality to those viewed on-site.
The method is of comparable quality to WENO schemes, but with optimally local stencils (performing updates in time by using information from only a single adjacent grid cell).
US studies of foreign-trained nurses (Cortés and Pan 2012) and doctors (Norcini et al. 2010) find them to be of comparable quality to their US-trained counterparts.
