I was searching for the bases you guys use for many of your armies (the ones without the beveled edges), since I really like the look. I found on a previous post that you recommend Litko bases. I was wondering if any of you have used their "magnetic bottom" bases? If you have used them, how did you find them? Were they strong enough to stick to a magnetic sheet if I put basing material over top of the sheet? Could they hold metal models? (redoing my mono daemons of khorne finally, and I have a lot of 5th ed bloodletters). Do you recommend the magnetic material or do you think it is better to just get their basic wooden laser-cut bases and add my own rare-earth magnets to the bottom instead? Let me know what you think!
Both Jayjack and Domus step up to help John out!
I've used the Litko bases and used to always recommend them. I tried their magnetic sheeting but it wasn't enough for metal DE models so probably won't cut it for those older Bloodletters.
I currently use the same type of bases (no beveled edges) but I got them in bulk at Adepticon from GF9 I believe. You can fill up Chinese take-out boxes for a very reasonable price of various sizes of these bases. If you can get there I recommend it.
I then simply drill holes and add rare-earth magnets into the bases (1 for most infantry more for bigger models).
For movement trays I've completely moved on to Hollow Tree (http://hollowtreestudios.com/) movement trays 100% of the time with metal inserts from Shogun Miniatures (http://shogunminiatures.com/) for magnetizing.
Hollow Tree has a proven track record for high quality and reasonable delivery times.
Those Shogun inserts are steel and the rare earth magnets grab hold and nothing moves. Very nice! (*Shogun inserts / trays can have a longer wait time - heads up. They are worth the wait)
I've long been an advocate of ditching the beveled bases and going with flat, but that's a rant for another day. I've used Litko bases, laser cut my own, and most recently I've been using Shogun Miniatures bases and trays.
Litko makes a decent product. I used very thin(0.8mm) plywood bases and attached their magnet bases to the bottom. Pros were the cost, cons were warping of the thin material (a lot in the case of the cav bases) and it's pretty tedious to attach the bottoms when you have a lot of bases. I also used the 'rubber steel' sheeting in my trays. The models were metal, on the smaller side as they were historicals but still heavier than plastic. They held ok, but the weakness is in the 'rubber steel' more than the magnet, so I wouldn't call it great. Careful you don't hit too many bumps when driving.
My new favorite is Shogun Minis. I use both their bases, which are plastic and have the magnet already attached, and their flanged trays. If you like a bulkier tray, then you can buy their flats and just use them as an insert. The combo of magnet on real steel is powerful enough that I can hold my metal unit of Black Orcs upside down. Cost is low, and they work great. Wait time varies, and it's a little awkward to order(email, no click type webstore) but I love the product so I deal.
Others have had a lot of success buying piles of laser cut MDF bases, and drilling them for rare earth magnets. A little more work than I care for most of the time, but RE magnets on a steel insert is about as solid as you're going to get. It's also going to be the best option if you want to hold through basing material. The sheet magnets can be strong, but they really need that surface contact. The RE magnets are strong enough to pull through, especially if you have more than one per base. Do a google search or check ebay, you should be able to find a few places to grab them. For your specific questions, this would be my recommendation.
So yeah, there's options. There's even a few places out there that make steel bases, and you put the magnet sheet in the tray. Not my favorite, but it's available. At any rate, here's some places to go looking, and good luck!