The best dealers are here on this forum. Always remember what this hobby is: buying and selling contraband items. If you can grasp the nature of the thing, it becomes more clear to you what to expect.
All the dealers on this site can be trusted with your orders. Some have great web sites, and some have NO web site. Some dealers here receive more negative feedback than others. This can be caused by trying to grow too quickly and losing control of your business or being small to begin with and trying to handle the flow of orders from these large forums. Some dealers are "companies" and some are one-person shops.
The dealers mostly buy the exact same watches from the factories or from a watch bazaar. Moving from dealer to dealer will not improve the quality of a watch replica.
That said, some dealers cater to the low end, offering mostly quartz or a21j watches. That is by design, and not because their "factory" builds worse replicas ... it's marketing to a different crowd of buyers.
The speed of delivery depends on a few things .. did you want to pay for EMS courier shipping or will you only pay for Air Mail (5 days or two weeks, your choice) .. also is it a pre-order of a hot piece, where you will have to wait a few weeks for the watch to become available due to the huge demand.
All the dealers here "stand behind" their sales, since it's a prerequisite to being a trusted dealer. You get an opportunity to reject a watch on a cosmetic basis via approval photos sent before shipment. Then if it arrives to you broken you have the option of returning it for repair or replacement. If it is seized by Customs in your country, it will normally be replaced (ONCE) free of charge.
About communication: Some dealers are much better with this than others. A rule of thumb, tho, is that dealers who are willing to hold your hand and spoon feed you also charge the most money for their watches.