"If this was a private equity float the price would have been higher," said Gaynor, who has criticised the bookbuild process used for the forthcoming float of private equity-owned glass supplier Metro Performance Glass.
Vista provides management software used by cinema operators for online ticket booking, food and beverage sales and staff rostering.
It will raise $40 million through the listing, expected to take place on August 11.
Existing shareholders - who will retain a 47 per cent stake in the company after the IPO - would sell 22 million shares, taking the total offer size to $92 million, the company said yesterday.
The IPO price values the firm at $188 million.
The retail offer opened yesterday and will close on August 1.
Vista, which has customers in 63 countries, has said it will use the proceeds of the float to repay debt and boost its stakes in two companies - New Zealand film analytics and campaign management software provider Movio and Netherlands film distribution software developer Maccs.
Vista has forecast a net profit of $8.1 million for the 2015 financial year, but dividends are not expected in the 2014 and 2015 financial years while the company focuses on growth.