Surprised at Fish Finders I've tried

Had a Bottom Line 4200 Fishing Buddy I thought I liked due the big screen display. I accidently fried it. Bought 3 different Bottom Line Fishing Buddy's off E-Bay....listed as one lot...as "parts & repairs only". One was the 4200....a Bottom Line II and a Bottom Line 2250. And aquired a 4300 free for shipping only. Good news. Got my Bottom Lline Fishing Buddy 4200 working fine again. Then fixed the Bottom Line II and it is working fine. Could not fix the 2250. But now I have three that work. So one lesson is that an E-Bay parts item might be fixable. Two of the three I got now work fine. No manuals though. Oh....BTW they were listed at $100 plus shipping.....nuther lesson learned. He took $55. Don't have to offer the asking price......But the surprise is this. I went out yesterday with the three working ones. Total surprise. The 4200 and the 4300 both had 5" screens I think. But their grayscale did not show up well at all in this sunny day. In fact pretty worthless. But the Bottom Line II showed up great! Had no knowledge about the 4300 or the II. The Bottom Line II is now my favorite. 'tis a portable...so I will use it on my 8' Pond Hopper abd on my 8' inflatable as well. Just provided as info for y'all. You are probably using newer better ones anyway.
jim