The good: clean and very comfortable room, quiet, good quality beds, good airconditioning, instant coffee facilities in room, reasonable breakfast included in very good online room rate, nice shower area, nice work area, free fast wifi, very nice very large lounge including bar open till late, computer corner, quick check in and check out.
The bad: not much really. No in-room safe. Location in office district is pretty desolate in the evening. Parking costs 15 Euro in good parking garage opposite the street, but when we left, the parking exit was open and we could have saved ourselves spending the 15 Euros. Suggest before you check out to have a quick peek at what the situation is :)
The hotel is about 10 minutes driving (no traffic jams assumed) from Schiphol. I will however next time most likely take a hotel again at Schiphol itself, since that eliminates even more uncertainty from the trip schedule ... e.g. you can already park your car at long term parking P3, no need to drive a short stretch from Hoofddorp over the A4 which might be congested, etc. This comfort factor however will come at a price, the Holiday Inn Express is a very good quality hotel at a very competitive room rate.