I hunt mainly relics as well as coins and jewelry.
I have had the Ace250 for close to a year and got the Tesoro Silver uMax less than a month ago.
Both machines are good. I found lots of great stuff with the Ace. My only real complaint about the Ace is that it would go nuts over trashy old house sites because of the nails. Done everything we could to get it to stop "chirping" over the nails. The closer to the surface the nails were, the worse the machine would act. The Silver doesn't do this. You will hear a few pops and crackles but, you absolutely know when you have a good target.
The Ace has good depth, but the Silver beats it in depth.
The Ace only has a 2 year warrenty where the Silver has a lifetime warrenty.
The Silver has more coils that you can purchase making your machine do more.
The Silver is alot lighter and better balanced then the Ace.
I like not having the Target ID on the Silver. In my experience the Target ID on the Ace will lie to you more times than not.
The Silver stock coil already has a cover over the coil. The Ace stock coil does not.
Last year if I would have bought the Silver, I would have been buying a new coil or two to make my machine do more instead of buying a new machine this year. Don't get me wrong I think the Ace is a great little machine. It's just that for about the same price I could have had alot better machine that suited my needs and is also backed by a lifetime warrenty.
With the Ace250 I bought the Pro Package that includes the 9x12. It gives the Ace a bit more depth and coverage area. When I bought the Silver I went ahead and got the 10x12 coil.... which I have named the steering wheel. It gives me more depth and coverage area. Both of the larger coils will cut your search time in half.... litterly! They are both heavy and the machines become very unbalanced making you wear down quicker.
Last year I was looking at the Ace and Silver. Last year my biggest deciding factor was the free gifts I got with each unit. Funny how I don't even use those free gifts any more. Those free gifts ended up costing me alot more when it was all said and done.
I search with my brother in law. We bought our machines at the same time..... both sets. Both of our Aces act the same and both of our Silvers act the same. Making it more fair to judge the machine since one or the other isn't a fowled machine.
You really can't go wrong with either machine. If I was buying again I would pick the Silver over the Ace.