I'd say it was priced very high, regardless of the lens - unless you have an Apo-Rodagon there, which would be unlikely. You can easily find a much higher quality enlarger for that price. For example, a higher quality machine will be more robust, easier to align, have a better negative carrier and is more likely to last decades without needing parts or service etc. etc. You can look for a high-end Durst, a De Vere or a Leitz machine in that price area.
EDIT: regarding format, it seems the 356 will do up to 6x6, I was thinking of a different Vivitar machine, oops.
I got lucky with my De Vere, but it was still cheaper and included a complete Jobo setup too ! In order to make your final choice a bit 'future proof' look for something doing at least medium format, as that will remove the biggest hurdle to printing bigger formats in the future. A physically larger enlarger will also make it possible to make larger prints more easily, or to use a smaller section from the negative to make your print with. A colour-head will be necessary if you ever want to try colour-printing of course, but can also be used with multi-contrast paper almost as conveniently as filters.
The secondary benefit of a colour-head would likely be a brighter light-source with a bulb that is easier to find, as most condenser-heads use a special opal bulb of relatively low power which is less well stocked these days. Note that there is still a difference in precision of manufacture and light quality between the photo-quartz bulbs (used in most colour-heads) and household ones of nominally the same fitting.
