The Ryobi One system seems to be very popular amongst Workshoppers and if you're already into the One System, buying the “skin” or “bare” version is the way to go, as you already have the charger & batteries.
For jobs like grout removal, any tool will do the job, but if you later want to do detailed restoration work, then there are quality tools out there and they will pay for themselves in no time.
In my case, I started off with a Bosch multitool from their green product line (budget sector), but it soon let me down. I replaced it with a Fein multitool and I'm super impressed with it.
I initially purchased a multitool with the purpose of removing the chocolate brown wood stain (‘70s build), so that I could expose & preserve the beautiful wood on our cedar slatted windows. Strangely, the Fein was able to sand right to the very edge of the right angle joins, where the cheaper knock off had left a 1-2mm strip of stain untouched.
In summary, multitools are brilliant and a vital addition to any tool collection. They're extremely versatile due to the enormous array of attachments and they are able to get into awkward areas where conventional sanders wouldn't be able to reach. - Andy_Mann
Like all tools, you get what you pay for. Though in the case of oscillating tools it's more about the quality of the blades. Cheap blades don't last long or do a very good job.
With electrical tools try and buy the best you can afford. The cheapest invariably need to be replaced with the higher price point so don't waste your money being seduced by "bargains".
If you are looking at a tool where accuracy is paramount, such as a slide compound saw, then go for the top of the range. These tools will give you repeat accuracy over and over, that cannot be said about the cheaper variety. - pursya
I have the Ryobi One+ and it is a great little unit. If you already have a couple of the Ryobi One+ tools then this would be a cheaper option. It depends on what you want to do with the tool, and of course, the cheaper the nastier. I have used mine to de-grout our main bathroom, trim electrical conduit, break-out plaster/render and trim small pieces of timber. Get good quality blades as the cheapies blunt very, very quickly. - darylhewston
I recently had to remove some skirting boards but could not pry them off due to the height of the carpet. Out came the multitool with a Diablo metal cutting blade and simply cut through all the nails behind the boards and lifted them out.
The current Ryobi One+ version has a detachable head and you can get more heads to fit that will turn it into various other tools such as a jigsaw or impact wrench. It wasn't marketed to do so in Australia but the clips are just hidden under the rubber grip. You can buy the range of AEG heads from Bunnings that will suit it.
Buy good quality blades. I really like the Diablo ones and they seem to last pretty well. - JP_Finlay