What I like about Parked.com is that they give you a bit more freedom when picking your keywords and the images for your site. They even allow custom content (if you buy typos for your domains like I do, you can use this custom content to link to your main domain), page title, meta description, and meta tags, which you can use to put a bit more weight into your site. The statistics is not the best in terms of details, but it is very user friendly. Parking them there won't hurt you.