For a man who single-handedly made at least 20 of the greatest trance tracks of all time, calling this his best work is probably a biiiit of a stretch.
It's a cool tune that sometimes pops back into my head though. The most interesting thing is probably how it bears zero resemblance to the original track.
Grooveline was the copy+paste follow-up release to Blockster (Brandon Block)'s "You Should Be...", a Bee Gees sampling house tune that was huge around late 98/early 99. Grooveline only spent a single week in the UK top 40, and was released by Ministry of Sound 2 weeks after ATB's 9pm Till I Come entered the charts at #1, so they had probably concentrated most of their promotional efforts on that. Also in the charts that week were Yomanda - Synth & Strings, Gouryella - Gouryella, Chicane - Saltwater, Space Brothers - Legacy (Show Me Love) (also including a Matt Darey Remix).