The Standards of Care for the Health of Transsexual, Transgender, and Gender-Nonconforming People has a good summary of studies (starting at page 229 (PDF page 65)). All quotes are from the standard of care (not in order though), and I linked to those studies that I could find freely available online for easy reference.
These studies measure more concrete things than "quality of life", including rate of regret (relevant as your blog article mentions this), mental and physical health, sexual satisfaction, etc.
Since the Standards of Care have been in place [meaning since 1979], there has been a steady increase in patient satisfaction and decrease in dissatisfaction with the outcome of sex reassignment surgery
This study [J. K. Meyer & Reter, 1979 [only abstract]] focused on patients’ occupational, educational, marital, and domiciliary stability. The results revealed several significant changes with treatment. These changes were not seen as positive
Participants in that study [Pauly, 1981] had much better outcomes: Among 83 FtM patients, 80.7% had a satisfactory outcome (i.e., patient self report of “improved social and emotional adjustment”) [...] Among 283 MtF patients, 71.4% had a satisfactory outcome
The findings of Rehman and colleagues (1999) and Krege and colleagues (2001) are typical of this body of work; none of the patients in these studies regretted having had surgery, and most reported being satisfied with the cosmetic and functional results of the surgery.
A prospective study conducted in the Netherlands evaluated 325 consecutive adult and adolescent subjects seeking sex reassignment (Smith, Van Goozen, Kuiper, & Cohen-Kettenis, 2005 [only abstract]). Patients who underwent sex reassignment therapy (both hormonal and surgical intervention) showed improvements in their mean gender dysphoria scores, measured by the Utrecht Gender Dysphoria Scale. Scores for body dissatisfaction and psychological function also improved in most categories. Fewer than 2% of patients expressed regret after therapy.
The vast majority of follow-up studies have shown an undeniable beneficial effect of sex reassignment surgery on postoperative outcomes such as subjective well being, cosmesis, and sexual function (De Cuypere et al., 2005; Garaffa, Christopher, & Ralph, 2010 [only abstract]; Klein & Gorzalka, 2009 [only abstract])
The standard of care then goes on to list some studies showing less beneficial results, but criticizes them for bad methods or comparing post op trans people with cis people to show that their quality of life is lower (instead of comparing them to pre op trans people or measuring increase/decrease in quality of life of individuals).
The swedish study you link to also has a good list of references, here are some quotes from them that I think are relevant:
80% of individuals with GID reported significant improvement in gender
dysphoria [...]; 78% reported significant improvement in psychological
symptoms [...]; 80% reported significant improvement in quality of
life [...]; and 72% reported significant improvement in sexual
The results showed that 3.8% of the patients who were sex reassigned
during 1972-1992 regretted the measures taken. [...] The results of
logistic regression analysis indicated that two factors predicted
regret of sex reassignment, namely lack of support from the patient's
family, and the patient belonging to the non-core group of
After SRS, the transsexual person's expectations were met at an
emotional and social level, but less so at the physical and sexual
level even though a large number of transsexuals (80%) reported
improvement of their sexuality.
Chris Hydes statements (eg "there's still a large number of people who have the surgery but remain traumatised - often to the point of committing suicide") are not the result of a study (as in published, peer reviewed), but just research he did for The Guardian.
The Guardian also says this: "Research from the US and Holland suggests that up to a fifth of patients regret changing sex. A 1998 review by the Research and Development Directorate of the NHS Executive found attempted suicide rates of up to 18% noted in some medical studies of gender reassignment.", but doesn't link to it, nor cites it correctly. I could not find it. But it seems that they infer from an 18% suicide rate that 18% (up to a fifth) regret sex reassignment surgery, which doesn't seem like a reasonable conclusion to me (and I doubt that the NHS made this conclusion).
As for the swedish study, it is a study comparing post op trans people to cis people, so it doesn't say anything about the success or failure of gender reassignment surgeries (and it doesn't try to do this either).
The linked blog post also mentions a 41% suicide rate for transgender people overall, but I agree with you, I don't see how that is relevant to sex reassignment surgery.
The only actual study showing adverse effects of gender reassignment surgery I could find in your links is the 1979 study by Meyer & Reter.
The sources I could find highly suggest that the quality of life of trans people who want SRS increases after SRS, and the majority of trans people do not regret SRS.
The linked claims to the contrary rely on decade-old studies or purposefully misrepresent the results of more recent studies.