Protek is great, I believe Scotskier uses one and Smoothrides had one for a while when he was mobile. Nothing but good reviews.
Swix just isn’t well built, lots of plastic, but then it’s also at a very budget price point as far as edgers go.
I’m very much a buy the right tool the first time and based on feedback of guys I know with them I’d pass and pony up a few more bucks for a proper tool (razor tune being cheaper and Snowglide and trione if one wants to go full bore)
My two cents, after living with the Evo for a bit, is that it's solidly built for the higher-end home-tuning market.
I did a full tune (sharpen edges, quick bronze brush, and wax, not including final scraping) on three pairs of skis Monday night, in about an hour and a half, including pulling back sidewalls on one pair. One pair (my touring skis) had not seen any edge work in..erhm..a while. The other two had a few hard-snow days since the last tune. I took one pass with the coarse disc on the beat-up touring skis (after knocking down the damage with a ceramic stone), one pass on my girlfriend's all-mountain skis with a medium disc, and one pass on my slaloms with the fine disc. I think the total time on edges was probably under 40 minutes. Getting the same results with hand tools would have easily taken 1.5 hours, maybe more given the condition of the touring skis, and the ease of keeping things up means that I expect I'll have sharp skis more often. I suspect any power edge tool would have similar benefits, although I do have to note that the ease of bevel swaps on the Evo is really nice when going between race skis at 3 degrees and all-mountain skis at 2 degrees (I could set them all to 3 degrees, I suppose, but that's a different discussion).
For my money, it's easy to justify the Evo pricepoint, even at MSRP, given the time savings. I can't say the same about justifying three times that for a ProTek or similarly priced tool, for the same reason my garage is full of decent hand tools but not Snap-On or Mac quality—I'm not using them all day, every day, or even all day twice a week. The plastic casing doesn't bother me at all; the tool still feels solid in my hand.
I haven't done a real comparison to the RT—as noted previously, I had a limited-time opportunity to get the Evo at a pricepoint that short-circuited further comparison—but I wouldn't write the Evo off as not being well-enough built for doing a few to a handful of pairs once or twice a week. If I was tuning 12 (or more) pairs each night, most nights, I might feel differently.
I'm hoping I still feel the same way years from now, but only time will tell on durability.