I've stayed at the holiday Inn Express "royal mile" a couple of times since it recently opened. It's actually at 300 Cowgate, behind the royal mile. If you turn immediate right out of the hotel and walk along the cobbled street it takes about 100 seconds to walk to the royal mile. when you get to the royal mile turn left to the castle or right to Holyrood, both easily walkable.

Waverley station is 5-6 minutes walk away (I walk quite quickly). Best idea is to get a taxi to the hotel firts time, or you stand a good chance of not finding it. Getting back to the station is easy. Turn left out of the hotel then first left. Go across the cross roads and follow the road. Cross over the next road and you are at the station entrance.

This is a typical holiday inn express. It's quieter than the one at Picardy place. there is little traffic noise to be heard as the rooms all face sideways on to a small street or church. High rooms on the right have a partial view towards Arthur's seat hill, which is a nice walk (appx 1h20m to the top and back). Otherwise no rooms are better than others. Some rooms on ground floor.

This express is just like any other you will go in to. the notable differences in the room because it's new are:

Individual airconditioning (partially effective)
Bluer lights in the bathroom
Toilet flush badly located behind the seat back
poor low voltage reading lamps
Nice widescreen TV (Still only a few channels)
The sofa bed is VERY hard if you have to use it

Everything is still very new (04/08)

The lifts require room keys to operate.

The resturant is downstairs, and the compliemenary breaksfast is the limited-choice but adequate cold continental buffet. Muffins smaller than most expresses. Not enough seating at peak times. Widescreen TV to watch breakfast TV while eating.

Only breakfast is servered, no evening meal, no room service. There are plenty of places to eat nearby at most times of the day.

The receiption staff are generally VERY friendly.

Car parking 20 yards away from the hotel (left) in the carkpark behind the traveloddge is £10 a night (change or telephone payment required, no notes), or free overnight on the street in a few places from 6:30PM.

Really good Old Town location. Secure parking one block away.
Room was very clean, comfortable.
Staff were cheery and helpful.
We needed a cheap, central stopover - basically to avoid driving home late after an event in Edinburgh and all in all, this was exactly what we were looking for.

We walked from train station, it was a little hard to find, call for exact directions. Rooms are small but clean, modern. Breakfast was good, fruit, cereal and breads. Not too far from train station once we figuered out directions. We walked to the castle and used site seeing busses for other transport.

This hotel opened recently and it is spic and span inside. Be advised that it is not actually on the Royal Mile, but a several minute walk away. The rooms are of a good size and you can open the windows. The only problems with my stay were the heater not working very well, despite having maintenance look at it, and the front desk's inability to do wake up calls. The breakfast was the usual Holiday Inn fare. It has a great central location and I would recommend it if they sorted the problems out.