I paid around £200 for my Drulov and I love it. Once i had got everything set up as I wanted it is fantastic.
There is a lot of hidden adjustment which can be done with these, especially the trigger mechanism although it does need to be stripped down for some parts.
The only downside is that if the trigger is not adjusted properly and it is set too light you can have a problem with the pistol going fully automatic on you with all 5 shots disapearing in one loud bang along with a chunk of your gas, but this can be sorted with careful setting up and not getting too heavy with the power setting.
AA s200 with BSA contender 8-32 x 50 - .22
AA S410 with 4-12x44 MTC Viper (.22 and .177 barrels)