The Golf GTD is a fine car for what it is. It does not have the reflexes, agility or feel of the RS Megane or the same character from its engine. I've driven an RS Megane...
However, I doubt you'll be disappointed, the Gold is quiet, comfortable, refined, with good grip and reasonable precision from the handling - you can even get it to be a little playful from the rear in my experience. The base performance is pretty good and it comes very well equipped as standard. Oh, it is reasonably economical, I've averaged 47.5 mpg in all driving - a fairly even mix of everything - over 32K miles...
There's the odd problem but nothing that I would call serious - mine has had the vertical parts of the spoiler round the rear windscreen... and that's it for mine, at least.
Those that have had a remap/tuning box have reported good results...
All-in-all, there's little the Golf does badly.. to me it lacks a little spark (but I have something else for that) and as a company car it is very good with low emissions...