I thought this too....Went to local Kubota dealer who also carries Echo, Shindawa. Was looking for weed whacker & chainsaw. Asked him what was different about his Echo vs the ones Home Depot has. He went on about how those are "consumer models", shorter warranty, nobody would work on them, NOT the same as what he carried. His were all "professional models" built for commercial use, much better overall.
So I wrote down a few of the model #s of ones I was interested in so I could do more research, read reviews, etc. Models on Home Depot website were exact matches. Nothing different in any way. Same warranty, same price, same everything. And not a case where almost same model # but last character is different or there's an extra letter/number on one vs the other.
Now I'm sure there is the added benefit of having their service guys do initial startup & check it over, somewhere to take it if it has issues later on. But this is why I went to HD instead (other than being lied to), & thought it was kind of big.....If I bought it & it had issues I could just take it back to HD and exchange for another or get my $ back. Dealer, nope, just repair it (and be minus a machine for as long as that took). What if I just didn't like it? Too big, too small, too heavy, awkward to use, not powerful enough, whatever - just there could be something I found once I started using it I really disliked. From HD, just return it. From dealer, stuck with it.
Now for Stihl, some Husq, Shindawa, Red Max, etc, dealer is only option, and would have been fine with that if those were model I chose. But since I decided on Echo anyway, to me it didn't make any sense to get from dealer instead of HD. Price same either way. I don't run a landscape business, make my living from these machines, or maintain huge acreage. I could see wanting the dealer if I was wearing out bump heads every few months or something from putting 60 hrs a week on the machines..... But wouldn't have buying the models I did in that case anyway probably. I'm not saying HD or dealer is better/worse for anyone else if they want an Echo. Just in my case it was better to go the HD route because I wanted the option to simply take it back & make it their problem if for any reason I disliked it.