Scanner Reviews: LPI Descreen setting?

Factual Questions
1

Do any current inexpensive (<=$100) flatbed scanners have a descreen setting that you can set the lines-per-inch on? I have an old Umax scanner that allows this and it -used- to take perfect scans. It started to get fuzzy and it is ~5 yrs old so I went shopping for another, but I couldn’t find anywhere that did very technical reviews that said if they have this feature or not. I (just now) bought a Canoscan Lido 30 (because I couldn’t find any info out anywhere that was useful anyway!) and it has a “descreen” check box, but the results are lousy. WIthout the descreen checked the results are simply unuseable for scanning any kind of printed material. With the descreen on, the results are a lot better, but simpy not perfect.
…
And I know that Photoshop has a descreen filter also, but that’s crappy too-you can’t fix a bad scan with a filter. If you set the Umax scanner’s descreen to the same LPI as the source document, it nailed it perfectly. I had to ditch the Umax as it had become loud and clunky and took 15 minutes to scan a whole page at 300 DPI while descreening at 175 LPI (it used to go a lot faster than that!), and since it was a parallel-port scanner, the computer locks up during the time it is operating the scanner.

This isn’t a hardware matter but a software one–are there any sites that actually review in detail the software features of these things?
~

2

We’ll I recently bought a Microtek Scanmaker 5800 for a little less than $100 that lets you pick one of 4 (IIRC) built-in descreen settings. So far (I’ve only had it a month) it’s given me impressive results when I scan, say, a newspaper photo on the “newspaper” setting.

It is not, however, infinitely adjustable. I wanted to scan a laser print-out which I calculated to be something like 40 l.p.i. It would not accept the number.