If you have the right setup both procedure produces good results. The consumables are more expensive with the photo process and they age. The up front costs for toner transfer are greater due to the cost of laminator and laser printer.The photo process is more reliable and yields higher quality boards but you need to buy photo-resist or pre-sensitised board so it works out more expensive.
You could go one further step using photo transfer. There are small print shops making advertising stuff for small companies to distribute in households. Many of them also have Gerber photoplotter equipment.However going on my research I'd say photo transfer is probably the best and most consistent method.