We are thinking of buying a tiller for our neglected garden, both for
current "garden beds" and to make new ones by cultivating the soil
(now a collection of beatuful weeds on a very uneven ground), then
just keep tilling until the weeds are decreasing in density. Finally
mix in soil improvements etc. and then use shallow and/or narrow
tilling to help keep weeds down.

Last time I did it with spadework - lots of it, and the garden beds
masses of weeds shows I made a good job of preparing the soil. Now I
am older and lazier (and my back hurts more).

My brother (in Sweden) sells the Mantis tiller and he tells me that a
Mantis is what I should have. However, these are rather expensive
outside USA, including in Australia.

Therefore I would like some advice on
1) would a tiller be of great / some/ little help?
2) is a 4stroke engine to be preferred above a 2stroke one?
3) is a Mantis worth the extra money?
4) or, what tiller / type of tiller should I buy?