I sell a whole list of rack brands at a bicycle shop.
Usually left off of internet rack discussions is the bicycle type and the personal makeup of the person.
- Got an 17 or 18 pound road bike?
Those are easy to get on the roof, easy to remove the front wheel and securely lock in a fork mount, and something that grabs the frame might not be desirable, especially with custom paint or super light tubing. The lower profile of the handlebars in a fork mount will also cause less clearance issues with drive-thru's, parking structures, etc...
- Like to ride 45 pound hybrids or downhill or "all-mountain" bikes?
These are much more difficult to get up on top. Through axles are more of a pain to fit to fork mounts. Upright racks that allow the front wheel to stay on mean the handlebars are UP THERE, and may fit low hanging trees, drive-thru's etc... Mountain bikes can be wet, muddy, etc... after a good ride.
- Are you short or tall, big or small? A 6'2" 220 pound male can easily put a 35 pound all-mountain bike on top, even on an SUV, because he can probably stand on an open door, hold his body up with one hand and one-hand the bike onto the rack. A 5'3" woman will have a much more difficult time doing the same.
Also keep in mind the following:
- Hitch racks, while easily accessible to smaller people, are usually HEAVY! If you're planning on a small person installing and removing the rack, keep that in mind. Some "accessibility features" work better than others, some move with finger tips, some require serious strength to operate. TRY IT BEFORE YOU BUY IT, with and without bikes mounted. A smaller person (or a larger person with a "Pro-cyclist" upper body ) may have difficulty installing a hitch rack alone, as the mass may be difficult to manuever into the hitch receiver. Roof racks are always available for use, as they're usually left on the vehicle.
- ALL racks can be outfitted to a similar security level.
- ALL rack security systems are defeatable by someone who really wants you stuff.
- Empty racks, without locks, get stolen off cars at trail heads and parking lots.
- BMX and kids bikes add even more things to think about.
Good luck!