I switched from GMAT to GRE, and I do not regret my decision 🙂
I started preparing for GMAT in February this year and gave my first attempt in April. I scored an abysmally low 550. I prepared for two more months and scored a 650. I thought I was capable of touching 720-730 in my next attempt but scored 630. I was shattered and could not apply to any B-school in Round 1 owing to my low score.
I spoke to my consultant about switching from GMAT to GRE and if it would hamper my chances. He assured me that most B-schools don't have a preference for tests. I scored a mere 313 on GRE in my first attempt, managed to improve it marginally in the next two attempts, and finally scored a 327 today (equivalent to a GMAT 720ish). Although 330+ is considered ideal, most B-schools have an average of 325. I might give it once more, but I am not sure of replicating the same performance.

I think the major reasons why I was unsuccessful at GMAT and managed to do well in GRE were:

1) The nature of the exam - There's too much pressure to get questions of increasing difficulty right. I also used to guess my performance during the test. Seeing an easier question made me panic at times. The section-adaptive GRE was a big relief

2) Verbal syllabus - I just couldn't improve my CR scores. GRE Verbal has Sentence Completion and RC and I found it a tad bit easier than GMAT CR (Scored 165 [96 %le] on GRE Verbal)

3) Data Sufficiency - I always struggled with this section, which is probably why the maximum I scored on GMAT Quant was 47

I studied mainly from Magoosh and used ScholarDen and Magoosh for questions. I am selling off both the subscriptions. Please DM me if you need them.

Good luck!