Styling maps is just an added feature. Their main uvp is simply "maps". Competitor and alternative to Google Maps, Mapquest, etc.

And there is also CloudMade as a choice for those seeking not to use Google Maps, Mapquest, Bing, etc.

http://cloudmade.com/

Both Cloudmade and MapBox use OpenStreetMap data. Leaflet ( http://leafletjs.com/ ) was created by Cloudmade and is the JavaScript lib for putting tiled maps on the web. Mapbox have their own version of Leaflet, but it's essentially much the same if all you want to do it drop pins, work with layers, choose a tile set.

Both are comparable, and both are strong in the same space: Custom styled, tiled maps. And both are weak in the same place: routing.

Not to say that they don't do routing, but it's certainly not their forte.

Thankfully the majority use-case for most sites and applications using maps is simply "show a map, drop a few pins here and there". So having this map look and feel like the site is actually a good selling point.

I expect routing to become more prevalent in the OSM world thanks to the fantastic http://project-osrm.org/ project.

That's surprisingly good. As in; for a complex route across London and factoring in one-way streets it produces something that looks realistic.

Only allowed me to pick car as a mode of transport, and unrealistically suggested I could get across 14KM of central London in 14 mins, but ignoring those things this is very nice.

Would love to see the path output of this added to Leaflet and a standard form of API emerge for Mapbox, Cloudmade, Google Maps, etc.

I believe that other transport modes (public transport, on foot) are in the pipeline, but the amount of additional compute power they need is significant

Also Public Transport route and connectivity information is frequently a bit patchy in OSM, but this is steadily improving.

I, ahem, might be working on a UK cycling router using OSRM ;)

You probably want to be talking to me... I run http://www.lfgss.com and am building community software to run cycling forums.

Email in my profile... that is, if you think we're your market.

Have you seen CycleStreets: http://www.cyclestreets.net/

Yep. It's great. This one will aim at a different market, really.

Interesting. What other market is there though? They do different confidences of cyclists and leisure routes already?

I used OSRM a while back for a longish car trip. Worked great.

Adding public transport, cycling etc. would be fantastic.

You should look into OpenTripPlanner by OpenPlans, they have built a multi-modal routing engine that can account for GTFS public data feeds as well as combining walking/cycling/public transit together to for a single route.

If you have a GIS dataset and you want to style it and serve it, your previous best bet was to use TileStache or something like that, to seed the png tiles for a zoom range. If you want to change the style, then you have to re-seed. I believe this allows you to 'seed' vectors and changing style is completely flexible.