Hi - the price will usually indicate that there are more exclusions in the cover - or that they have 200 telephone lines to sell you the policy and only 1 incoming line to deal with claims. :-)
If you know anyone who has made a claim and is relatively happy with the way it was handled then take their recommendation or use a broker - if you are stuck abroad, ill and desperate to get home you dont want to have to fight your insurance company or find you cant get through on the helpline.