Hello Heather , welcome to the forums !!! 
Are these guys going to replace it for you or are you just buying an LCD from them ? in any case you have to make sure that you have a record of everything you do with them (receipts, proof of purchase warranty details etc). If they have a phone number listed, call them up and inquire about few other items, not that you're really interested in them but just to see how their customer service is. You can search online consumer groups, see if you can find any information on them (good/bad ratings etc). Also check their return policy and DOA replacement policy and such. Im sure this is a major investment for you so its worth of measuring twice and buying once. Good luck !!!
[edit] forgot to mention, check how easy is to obtain an RMA and check their dead pixel policy !!!
Are these guys going to replace it for you or are you just buying an LCD from them ? in any case you have to make sure that you have a record of everything you do with them (receipts, proof of purchase warranty details etc). If they have a phone number listed, call them up and inquire about few other items, not that you're really interested in them but just to see how their customer service is. You can search online consumer groups, see if you can find any information on them (good/bad ratings etc). Also check their return policy and DOA replacement policy and such. Im sure this is a major investment for you so its worth of measuring twice and buying once. Good luck !!!
[edit] forgot to mention, check how easy is to obtain an RMA and check their dead pixel policy !!!