Patches use transdermal administration and have similar low health risks as injections, avoid the first pass through the liver problem of oral administration and have the added benefit that if you react badly to the supposedly inert ingredients in the administration method (the adhesive in the patch), you can pull it off. With an injection, if your system does not like the oil substrate used to transport the estrogen, you're stuck for a week or more. Transdermal application (patches or gels) requires similarly lower dosages when compared to injections. Oral administration requires the highest dosage.
With sublingual administration, there is controversy about how much is actually absorbed via the oral mucosa and how much ends up being swallowed and absorbed via the digestive system. If you need to avoid oral administration secondary to increased risk for thrombotic events (late transitioners and smokers in particular), I would ask your doc about patches or injections. Intramuscular injections are easy to learn how to do, and not very painful for most people. Definitely worth looking into.
Many women use the patches as they are easy, have one of the lowest effective dosages of any administration method and only need to be put on once per week. They are more expensive than injections though.