Now, keep in mind that most of the time, those who have the opportunity to evaluate new product entries tend to comment only on the nice things. Minelab, it appears, didn't hesitate to offer up a number of these to a respectful number of dedicated detectorists to 'sample' a variety of hunting environments. They have to know that we're all going to compare the performance of the X-TERRA 50 to a wide variety of makes and models that we each personally favor, and left the door open for us to voice honest opinions.
What does that tell you right off the bat? That Minelab knew they had a well thought out and efficiently engineered detector that had most of the bugs out. This was not a 'rush to production' like we have seen too oven in years past from many manufacturers. It has left me very impressed and as I am working on a second set of batteries I am finding the X-TERRA 50 a very difficult detector to put down, doing so only to pick up one of the others I am comparing it with afield.
We all got the stock 9" concentric coil which alone makes for an interesting feature to evaluate from Minelab since most of use are so used to their Double-D coils. There are other sizes and types displayed or mentioned in the Instruction Manual and the new model flyer, so we know they are coming. This is a very good thing because I, for one, enjoy using smaller coils most of the time because I hunt a lot of iron infested sites or those that have a lot of brush or building rubble. Look how many newer models have been released in this past couple of years that still do not have a smaller coil option from their respective factory, or even mention of plans for one!
So, I can't say this is a "downside" because Minelab is already working on the coil issue (and a unique one at that which includes operating frequency changes!!)
Usually, I do not use a coil cover except on smaller-sized coils that will be stuck in and under brush or near sharp and/or abrasive objects. One other important reason is the weight that they add. I know it doesn't seem like much to some people, but if you hunt with a coil cover on for about 30 minutes to an hour and then pause to remove it and start right back up hunting, you can usually tell the difference.
Once again, Minelab has addressed a concern of many hobbyists. After my first couple of hours with the X-TERRA 50 I did just that and, to my surprise, I couldn't really notice any difference in 'feel' or balance like I do from other brands. Better than the fact that the 9" coil cover is very lightweight is the fact that IT IS INCLUDED AS A STANDARD FEATURE! Nope, they took care of that before anyone could fault what they might consider a weakness or "downside."
From the time I first opened the box to the present I try to think of any strength as well as any weakness it might have and, to satisfy your question I can only think of two or three off hand.
It comes without batteries so you have to supply them, but most of us use AA batteries and have them, around anyway. What's 85