A huge disappointment. I only had wifi from around the time HeartGold and SoulSilver came out, and had really enjoyed using the GTS to actually get close to completing a Pokédex (before at some point only the really terrible trades were left up there). Should've really kept hold of a Glameow given its now the only thing preventing me from completing the Gen IV Pokédex haha
I hated having to steal time on the family's shared computer just to try to complete my game, especially combined with Nintendo/GF vastly underestimating demand and having to limit everyone to 1 hour per day.
Perhaps because I went to university during this time, it felt like the time before it was completely shut down was very short, especially compared to GTS which if I recall was functional for Gen IV for the duration of Gen V too.
I wouldn't say it counts as a swing...but definitely a miss for me :(