I've never used a 250 but have had a 350 for 6 months. I was in the same position you are now about a year ago. The 350 is a simple machine to use. It's so simple there is a real possibility you might outgrow it in a short time. That has happened to me and I am now buying an AT Pro. Yes it is 2x the cost of the 350, but if you are like me, I often regret "stepping slowly" into a hobby instead of just buying a machine a bit beyond my capabilities and growing into it. The 350 will find a lot of stuff. I found a very expensive ring and many many coins. It works and works very well. But simple technology will not peak your interest for a long period of time, if you are like me. If you enjoy and accept "simple that just works", get the 350. You won't be sorry. If you are fairly sure you will like the hobby, get the AT pro and save $300 that you would have spent on the 350. If you end up not liking the hobby, an AT Pro will be easy to sell and not loose your shirt. Not sure you could say the same about a 250/350. Hope that helps, Bud