hey Jer,
I've owned the 620 for just over a year now. overall, I'm happy with the purchase. you get a lot with the coscto deal; two internal cooking surfaces, two external shelves, underneath storage, cover and the return convenience should you decide it's not for you. there are tradeoffs though. the general consensus is thinner metal (perhaps?), no insulation or seals on the lid, which may be a concern living in colder temps. you could always get a thermal blanket, something I may end up doing. I need to get mine under cover first. I've cooked in the rain and cold using a makeshift lean-to but if you have a covered cooking space, you may be fine.
one of the biggest positives, and not necessarily unique with the 620, but it is quite easy to use and once I gave my wife a couple lessons, she's been using it quite a bit for baking during the summer, and even roasting some chicken the other day! I always smile when my traeger app alerts me to the preheat being complete while I'm at work and she's started to cook something
I ordered mine online because of free delivery and I think it may have been a sale too. pretty sure I paid $649, which I think is a great deal. be sure to watch for dents and lid alignment. my unit must have been on the bottom of the pallet because the lid sits slightly askew when closed. not a huge deal but something that made me frown.
the food temp probe will probably not be accurate, nor will the internal ambient temp sensor. mine ranges between 25-40+ degrees cool depending on how hot you're cooking. best to get a separate temp monitoring setup. I also recommend characterizing your cooking surface temps., I have hot spots and rotating the meat/food will get you the best results. I'm not familiar with the Elite but every grill will have it's unique qualities and it'll just take time to adjust to them. the Silverton is no different.
Wi-fire is very nice to have and has worked well for me so far. I'm also a big fan of the Meater probes and I hope that the recent merger with Traeger will bring positive improvements to both products.
one other thing I'll mention, if you don't want to spend the money on the convenient drip tray liners...the heavy duty aluminum foil at costco is quick and easy to use instead. and a vital tool for quick cleaning and ash removal is that little yellow shop vac at home depot (the name escapes me right now) and it also fits quite nicely underneath the grill in the storage cabinet.
the 500 degree temps are nice. reverse sear still works better than cooking a steak like you would a conventional charcoal or propane grill but the 620 does get hot enough for the finishing crust. I like the hot temps more for baking...desserts, pizza, etc.
bottom line, it's a very well behaved and nicely designed unit. If I didn't have one or mine disappeared...would I buy another Silverton instead of looking to the ironwood or one of the barrel style Traegers??? that's a tough question. they are kinda spendy but knowing now how nice it is to work with a Traeger, I'd say it's more likely than if I were going in blind never having used a pellet smoker.
hope that helps. good luck and let us know what you end up doing
-Steve