I haven't used Buildum, but I would just try to analyze what you are trying to achieve. Buildum is your property management tool, and there is promise of having it solve some accounting functions (which could be a major plus). If you have some experience in the back end, bookkeeping, reconciliations, depreciation, etc this could be a good option. Just make sure you are able to stomach any problems if they do arise.
QuickBooks Online, Xero, and the likes of products are specific for accounting functions so it's easy to rely on them for keeping your accounting in good order. If you need to hire a pro to do this it will be a breeze as far as finding people capable (choosing them is another story).
My biggest concern with placing all of your accounting functions in a fairly unknown software to Accounting and Tax professionals, is getting someone that will be able to assist in the process if you do have problems with your books in the future. QuickBooks and Xero are almost universal and it's fairly easy to find a pro that can assist with the tool. Of course using Buildum and QBO will require more work, but it might save time in the long run.
If you soley rely on Buildum, you just might have to pay a pro down the road to migrate the data into QBO or the like.
- Michael