In my first congregation I used an old classroom for my prayer space and I went there regularly. It was not a great looking space but it fit the bill. One of our members found out about my using the old classroom and he made it look a lot nicer and much more user friendly. I found that I could drop into a prayerful space more quickly there then any other space indoors.
We have a new prayer chapel in my current congregation and it is very nice. I have only been in there a handful of times and while it is nice it it harder for me to drop into a prayerful space there.
I think that the more we use a space for prayer the easier it is to drop into a prayerful presence. I also believe that it is not only us praying in the space but others too. I think that a place that is prayed in a lot becomes what some call a "thin space". A "thin space" is a place where the difference between heaven and earth is very thin. Another way to understand a thin space would be a place where the kingdom of heaven is more obvious.
My hope is that the new prayer chapel will become a thin space.