Dimension 5 was a long lived group which enjoyed some success back in the days and is now regarded as one of the classic goa acts amongst the old school fans. I don't quite share the enthusiasm and here's why...
The usual D5 formula is to have a soft, floaty synth line in the background, which on they paint small effects and the lead melody(s). It's precisely the fact the frame (ie. background) on most of their tracks is kept the same through-out the track that has made grow out of their music. Approach from a positive angle and you could say the repetitive nature is actually hypnotic and danceable - which I wouldn't argue against. But for an avid long time bedroom listener like me the missing subtlety in the background details is enough to create a feel of unfulfillment. I give them the credit of doing very well the standard goa recipe, yet I don't find they ever went past the comfort zone pushing the envelope of psytrance. Only on a few tracks on 'Transdimensional' they've created enough varied, contrast soundscape that I'm able to go back again and again without getting bored.
The initial impact D5 had on me years ago was enormous, 'Transdimensional' was one of the reasons I felt for goa trance. But after listening to psytrance for a long time and coming back to their stuff now the bare truth is, especially if speaking of works around 'Transdimensional', they are spare of ideas and lack progression within a lot of their tracks to the point you could as well classify them hard trance as goa (edit: This would apply only for material between 95-97).
Not to be all negative. Dimension 5 is a great group to start if you're new to goa trance, you might enjoy their music from the very first listen even. I've not mentioned 'Second Phaze' in the review earlier as I find it rather average, point being you should go straight for the magnum opus 'Transdimensional', it's also the easiest to get as Suntrip records was kind enough to repress it.